WO2019092046A1

WO2019092046A1 - Secure electronic payment

Info

Publication number: WO2019092046A1
Application number: PCT/EP2018/080515
Authority: WO
Inventors: Quirino Zagarese; Francisco Angel Garcia RODRIGUEZ; Piers POWLESLAND; Paolo GRECI; Laurence WITHERS; Eleanor Simone Frederika LOUGHLIN-MCHUGH; Romek Edward SZCZESNIAK
Original assignee: Yoti Holding Limited
Priority date: 2017-11-09
Filing date: 2018-11-07
Publication date: 2019-05-16
Also published as: GB2582113A; GB202008739D0

Abstract

A method of authorizing a secure electronic payment from a payer to a payee. At a digital identity system, an electronic message is received, which comprises a payer credential and identifies a payee system. At the digital identity system, a digital identity associated with the payer credential is accessed, the digital identity comprising: 1) at least one identity attribute or data for deriving at least one identity attribute, and 2) a payment token or data for obtaining a payment token, the payment token for effecting an electronic payment from the payer to a recipient of the payment token. At least one electronic message is transmitted from the digital identity system to the payee system to render the identity attribute and the payment token available to the payee system, for determining, based on the identity attribute rendered available to the payee device, whether to use the available payment token to effect an electronic payment from the payer to the payee.

Description

Secure Electronic Payment

Background

Payment fraud is a serious problem in the modern world and the problem is getting worse as more and more payments are made electronically. This applies to online payments in particular where the opportunities for committing payment fraud are rife.

One of the most common types of payment fraud is where a user's payment card details are obtained illicitly and used without their authorisation to make purchases online. A significant proportion of card payments worldwide end up being reversed (a so-called "chargeback") for this reason. Such payments often go through initially because insufficient checks are made to verify the identity of the person using the card details.

Summary

This disclosure provides a secure and efficient mechanism for making identity-linked payments. It has various applications, which include the combating of online fraud but also other applications where identity checks need to be made before accepting payment. One example is age verification when purchasing age-restricted goods.

This is achieved by incorporating payment tokenisation elements into a digital identity system. Within the digital identity system, a user can create a digital identity which can then be used to assert his identity (or some aspect of his identity) to another user or device. The digital identity comprises one or more identity attributes and/or data for deriving such attribute(s), and the user is able to prove his identity by sharing at least one of these identity attributes with the other user or device in a transaction conducted via the digital identity system. Identity-linked payment functions are provided by allowing the user to incorporate into his digital identity one or more payment attributes, which can be a payment token or data for obtaining a payment token such as payment card details. The payment token can be shared with the other user or device in the same transaction that asserts the user's identity to the other user or device. This allows the other user or device to verify the identity of the user based on the shared identity attribute, which in turn allows the other user or device to decide whether to accept payment from the user.

A first aspect of the invention is directed to a method of authorizing a secure electronic payment from a payer to a payee, the method comprising: receiving, at a digital identity system, an electronic message, which comprises a payer credential and identifies a payee system; at the digital identity system, accessing a digital identity associated with the payer credential, wherein the digital identity comprises: 1 ) at least one identity attribute, and 2) a payment token or data for obtaining a payment token, the payment token for effecting an electronic payment from the payer to a recipient of the payment token; and transmitting at least one electronic message from the digital identity system to the payee system to render the identity attribute and the payment token available to the payee system, for determining, based on the identity attribute rendered available to the payee system, whether to use the available payment token to effect an electronic payment from the payer to the payee.

Preferably, the at least one identity attribute of the digital identity has been verified by the digital identity system in that the digital identity system is sufficiently confident that the payer is the entity to which the at least one identity attribute corresponds. The payment token may be obtained independently of a trusted source of identity information used to verify the identity attribute, to which the identity attribute is anchored. The trusted source of identity information can for example be a document issuing authority, and the payment token can be obtained from one or more independent entities, such as a bank, or a payment service provider in combination with a bank and the like. For example the identity attribute may be verified based on a passport, driving licence, national identity card or other identity document issued by the document issuing authority, using data captured from the identity document. The verification of the identity attribute can comprise biometric verification. That is, the identity attribute can be verified based on a biometric identifier captured from the payer, such as a facial image or fingerprint. For example, the captured biometric identifier may be compared with a corresponding biometric of the identity document, such as a facial or fingerprint image or template. In embodiments, the electronic message comprising the payer credential may be received from a device of the payer.

The payee system may be identified by a payee credential comprised in the message and associated with the payee system.

The electronic message may comprise the payer credential and the payee credential is received from a device of the payer, the payee credential having been captured at the payer device The payee credential may be in the form of a sharing token issued to the payee by the digital identity system in response to a request from the payee.

The payee sharing token may be associated with a policy, which indicates a type of the identity attribute to be shared with the payee and indicates that the payment token will be shared with the payee.

A copy of the policy may be cached at the digital identity system in association with the sharing token, wherein the transmission of the at least one electronic message may be conditional on a matching policy being received from the payer device with the payee sharing token.

The policy may be displayed at the payer device when the payee sharing token is captured. The payee credential may be captured from a barcode or QR code presented to the payer. The barcode or QR code may be displayed on a display of the payee system for capturing by the payer. The payment token may be obtained from card details or bank details of the payer.

The card or bank details may be stored as part of the digital identity, and the stored details may be used by the digital identity system to obtain the payment token. The payment token or the data for obtaining the payment token may be stored at the digital identity system in an encrypted form, such that at least one payer key is required to decrypt them, wherein the payer key is provided to a device of the payer and is not retained at the digital identity system, wherein the method may comprise receiving the at least one payer key from the payer device and using it to decrypt the payment token or the data for obtaining the payment token.

The payer key may be provided to the payer device in an encrypted form, such that a payer wrapper key retained at the digital identity system is required to decrypt it, wherein the payer wrapper key is not released outside of the digital identity system.

The payment token or data for obtaining the payment token may be held in a database of the digital identity system, wherein at least one database key for locating the payment token or data for obtaining the payment token in the database is provided to payer device, wherein the at least one database key is received from the payer device with the at least one payer key and used to locate the payment token or data for obtaining the payment token for decryption.

The identity attribute may be an age-related identity attribute for determining whether the payer meets an age requirement before effecting the electronic payment. The payee system may be embodied in a self-checkout terminal and the self- checkout terminal may use the identity attribute to determine whether the payer meets the age requirement. The identity attribute may be a name, or a facial image or other biometric identifier of the payee.

The payment token may be obtained independently of a trusted source of identity information to which the identity attribute is anchored.

The identity attribute may be a data item captured from an identity document.

The identity document may be a passport, driving license, or other national identity document.

The identity attribute may be verified by comparing a biometric identifier captured from the payer with a biometric of the identity document.

The payment token may be bound to an identifier of the payee, such that it can only be used by the payee.

The payment token may be a one-time use only payment token.

The electronic message transmitted to the payee device may be in the form of a receipt, wherein a second receipt is transmitted to a device associated with the payer credential.

The second receipt may comprise at least one identity attribute of or derived from a digital identity associated with the payee credential.

The receipts may include matching transaction identifiers. The payer credential may be a one-time use only credential, and the method may comprise transmitting a fresh credential to a device associated with the payer. The payer credential may be validated at a validation service of the digital identity system, and the transmission of the at least one electronic message may be conditional on the credential being valid.

The electronic message comprising the payer credential may be received from the payee system, the payer credential having been captured at the payee system.

The payer credential may be in the form of a sharing token issued to the payer by the digital identity system in response to a request from the payer. The identity attribute may be an anonymous identity attribute.

The electronic message transmitted from the digital identity system to the payee system may comprise a link to a memory location at which the identity attribute and the payment token are published, thereby rendering them available to the payee system.

A biometric authentication may be performed by comparing a biometric identifier captured from the payer with biometric data of or associated with the digital identity. The identity attribute may comprise the biometric data for performing the biometric authentication at the payee system.

The at least one electronic message may also render available to the payee system an age-related attribute of or derived from the digital identity. The biometric identifier may be captured at the payee system and provided to a device of the payer for performing the biometric authentication at the payer device.

The payment token may be an authentication token for authorizing the electronic payment via an API.

The payment token may be a token for authorizing a cryptocurrency transfer.

Another aspect provides a non-transitory computer readable medium having executable instructions for authorizing a secure electronic payment from a payer to a payee, the instructions configured, when executed at a digital identity system, to implement the method or any embodiment thereof.

Another aspect provides a digital identity system comprising: a computer interface configured to receive an electronic message, which comprises a payer credential and identifies a payee system; at least one processor configured to implement the method or any embodiment thereof.

Another aspect provides a digital identity system comprising: a computer interface configured to receive an electronic message, which comprises a credential of a paying user and identifies a payment-receiving entity; at least one processor configured to execute identity management code which operates to: use the credential to access at least one attribute of a digital identity of the paying user held at the digital identity system, and create an electronic message for transmission to the payment-receiving entity, the electronic message comprising or indicating 1 ) the at least one attribute of the paying user's digital identity, and 2) a unique card attribute, and transmit the electronic message from the digital identity system to the payment-receiving entity; wherein the digital identity system is configured to verify that the paying user has received a bank card, wherein the unique card attribute confirms, to the payment-receiving entity, that the paying user has received the bank card, and the at least one attribute of the digital identity proves an aspect of the paying user's identity to the payment-receiving entity.

Embodiments may also provide a method of a digital identity system generating a sharing token for authenticating a bearer to a validator, wherein a data store of the digital identity system holds a plurality of attributes of the bearer, the method comprising implementing by the digital identity system the following steps: receiving at the digital identity system from a bearer an electronic sharing token request, wherein the token request identifies at least one of the bearer's attributes in the data store selected for sharing with a validator; in response to the electronic token request, generating a sharing token, which is unique to that request, for presentation by the bearer to a validator; associating with the unique sharing token at the digital identity system the identified at least one bearer attribute; and issuing to the bearer the unique sharing token; and wherein later presentation of the unique sharing token to the digital identify system by a validator causes the at least one bearer attribute associated with the sharing token to be rendered available to the validator by the digital identity system.

The sharing token is unique to each sharing token request. A user can request as many sharing tokens as he likes, and specifies each time which of his attributes he wants bound to that sharing token, which provides a flexible sharing mechanism. Each sharing token is bound to a fixed set of attribute(s), which is specified entirely by the token request such that the user has complete control over what data he makes available with that token.

In embodiments, the token request may comprise an associated policy defined by the bearer and the steps may further comprise: storing the bearer-defined policy at the digital identity system in association with the sharing token, wherein the at least one bearer attribute is only rendered available to the validator if the validator presents a matching policy with the sharing token. The policy defined by the bearer may be a bearer policy that specifies a type of the at least one attribute associated with the sharing token.

The method may comprise receiving from the bearer at the digital identity system a credential of the bearer, and validating the credential, wherein the sharing token is generated only if the bearer credential is valid.

The credential may be a one-time only use credential, and the method may comprise issuing to the bearer a fresh one-time only use bearer credential.

The at least one bearer attribute may only be rendered available to the validator if the validator presents, with the sharing token, a credential of the validator that is determined to be valid by the digital identify system. The presentation of the sharing token to the digital identity may also cause at least one attribute of the validator held in the data store to be rendered available to the bearer by the digital identity system.

The policy defined by the bearer may be a validator policy which specifies at least one attribute type that the bearer expects the validator to share with the bearer.

The at least one validator attribute may have the type specified by the bearer-defined validator policy. The token request may comprise both the bearer policy and the validator policy.

The validator credential may be a one-time only use credential, and the digital identity system may issue to the validator a fresh one-time only use credential to the validator in response to the presentation of the valid validator credential. The at least one attribute of the bearer may be rendered available to the validator by storing a version of it at an addressable memory location, and transmitting to a network address associated with the validator a validator receipt, which comprises a link to the addressable memory location.

The at least one validator attribute may be rendered available to the bearer by storing a version of it at another addressable memory location, and transmitting to a network address associated with the bearer a bearer receipt, which comprises a link to the other addressable memory location.

The steps may further comprise: storing a hash of the bearer credential and/or the fresh bearer credential in association with the sharing token at the digital identity system. The presentation of the sharing token by the validator may also cause the digital identity system to generate, in a master receipt store of the digital identity system, a master receipt comprising: the hash of the bearer credential and/or the fresh bearer credential; and an indicator of the at least one attribute rendered available to the validator.

The master receipt may also comprise an indicator of the at least one attribute of the validator rendered available to the bearer.

The master receipt may also comprise a hash of the fresh validator credential and/or a hash of the validator credential.

Each indicator may be a link to a respective addressable memory location at which a version of the indicated attribute is held.

The at least one bearer attribute may be held in the data store in association with at least one identifier of the bearer, wherein the sharing token may only generated if a matching bearer identifier is received with the bearer credential. The at least one bearer identifier may comprise: at least one biometric template of the bearer, and/or at least one secret known only to the bearer, and/or an image of the bearer.

The at least one validator attribute may be held in the data store in association with at least one identifier of the validator, wherein the at least one bearer attribute is only rendered available to the validator if a matching validator identifier is presented with the sharing token.

The at least one validator identifier may comprise: at least one biometric template of the validator, and/or at least one secret known only to the validator, and/or an image of the validator. A wrapper key of the bearer may be stored at the digital identity system, wherein the at least one attribute held in the data store is encrypted with a bearer key, and wherein a version of the bearer key encrypted with the bearer wrapper key is received from the bearer in the token request; wherein the steps further may further comprise: using the bearer wrapper key to decrypt the bearer key received from the bearer; and using the decrypted bearer key to decrypt the at least one attribute held in the data store; wherein the decrypted at least one attribute is rendered available to the validator when presenting the sharing token.

The attribute may be encrypted with an attribute key, wherein the message identifies a storage location of the digital identity system at which a version of the attribute key encrypted with the bearer key is held; wherein the decrypted bearer key may be used decrypt the at least one attribute by using the decrypted bearer key to decrypt the attribute key held at the identified storage location and using the decrypted attribute key to decrypt the attribute. The sharing token may be associated with the at least one attribute by storing the decrypted at least one attribute at the digital identity system in association with the sharing token. The wrapper key may be a device key bound to a single device operated by the bearer.

The bearer and validator attributes rendered available to the validator and the bearer respectively may be encrypted with a transaction key, a copy of which may be provided to both the bearer and the validator in response to the presentation of the sharing token to the digital identity system by the validator.

Each of the indicators in the receipts may be encrypted with a transaction key, a copy of which is provided to both the bearer and the validator in response to the later presentation of the sharing token.

Each of the bearer and the validator may be associated with a respective code unique to that entity (bearer/validator), wherein the method may comprise: generating a unique composite code by combining the code of the bearer with the code of the validator, wherein neither of the codes is derivable from the composite code alone; wherein in response to the later presentation of the sharing token, the composite code may be provided to the bearer and/or the validator by the digital identity system.

The unique code of the bearer may be derived from the bearer key.

The unique code of the validator may be derived from a validator key, with which the at least one validator attribute is encrypted.

Two different composite codes may be generated, each being unique to both that pair of entities (i.e. the pairing of the bearer and the validator) and to a different one of the entities (i.e. to one of the bearer and the validator), wherein that composite code is provided to that entity.

The sharing token may be associated with the at least one bearer attribute by storing a copy of at least a part of the token request at the digital identity system in association with the unique sharing token, wherein the later presentation of the unique sharing token to the digital identity system causes the digital identity system to retrieve the at least one selected attribute from the data store using the stored token request.

The stored request may be encrypted with a sharing key, a copy of which is issued to the bearer with the sharing token, whereby the validator must present the sharing key with the sharing token to access the at least one bearer attribute. The token request may comprise, for each attribute it identifies, a respective database key and/or at least one pointer and/or other data denoting a location of that attribute in the data store.

The token request may identify at least two attributes of the bearer held at different locations in the data store.

The token request may be one of a plurality of sharing token requests received from the bearer, wherein a different sharing token is generated for each of the requests that is unique to that request.

The sharing token is renderable as a bar code on a display.

Another aspect of the present invention is directed to a digital identity system comprising a computer system configured to implement any of the methods disclosed hereinabove or hereinbelow. Embodiments may also provide a bearer device comprising: a computer interface; a processor configured to execute a digital identity application, wherein the digital identity application is configured when executed on the processor to perform operations of: generating an electronic sharing token request, wherein the token request identifies at least one of bearer attribute in a data store of the digital identity system; transmitting the token request to the digital identic system via the computer interface; receiving from the digital identity system, in response to the electronic token request, a sharing token unique to that request for presentation by the bearer to a validator; and rendering the unique sharing token available to a validator, wherein presentation of the unique sharing token to the digital identify system by the validator causes the identified at least one bearer attribute to be rendered available to the validator by the digital identity system.

In embodiments, the unique sharing token may be received with a sharing key for decrypting the at least one bearer attribute, which the application may be configured to provide to the validator with the sharing token.

The electronic message may be generated in response to receiving a selection of the at least one bearer attribute from a user of the bearer device via a user interface of the bearer device.

The application may be configured to render the sharing token available by displaying on a display of the device a bar code in which the sharing token is embedded.

The application may be configured to also generate at least one policy which is included in the electronic message transmitted to the digital identity system, wherein the application may be configured to render a copy of the policy available to the validator with the sharing token. The policy or a link to the policy may be embedded in the bar code, and thereby rendered available to the validator.

The at least one policy may define at least a type of the at least one bearer attribute and/or at least one attribute type to be shared by the bearer in return for the at least one bearer attribute.

Embodiments may also provide a method of authenticating a bearer to a validator, the method comprising implementing by a digital identity system the following steps: receiving from a bearer an electronic message comprising a bearer key encrypted with a bearer wrapper key, wherein the message identifies: an attribute of the bearer held in a data store of the digital identity system and a storage location of the digital identity system at which a version of the bearer wrapper key is held; using the received message to retrieve the version of the bearer wrapper key from the identified storage location; using the located wrapper key to decrypt the received bearer key; and using the decrypted bearer key to decrypt the bearer attribute, wherein the digital identity system is configured to render the decrypted bearer attribute available to a validator when authorized to do so by the bearer. In embodiment the attribute may be encrypted with an attribute key, wherein a version of the attribute key encrypted with the bearer key may be held at a storage location in the digital identity system that is identified by the message; and the decrypted bearer key may be used to decrypt the bearer attribute by using the decrypted bearer key to decrypt the attribute key, and using the decrypted attribute key to decrypt the attribute.

A credential of the bearer may be received with the encrypted bearer key, and the remaining steps are only performed if the credential is determined to be valid by the digital identity system, and the method may further comprise: issuing to the bearer a fresh one-time only use credential of the bearer, and associating the fresh bearer credential with the version of the bearer wrapper key stored at the digital identity system.

Embodiments also provide a validator device comprising: a computer interface; a processor configured to execute a digital identity application, wherein the digital identity application is configured when executed on the processor to perform operations of: receiving, directly from a bearer, an electronic sharing token and an associated policy defined by a bearer; rendering the received policy on a display of the validator device; in response to receiving via a user interface of the validator device from a user of the device, a user input denoting an acceptance of the displayed policy by the user, transmitting an electronic message comprising the sharing token and a version of the bearer-defined policy to a digital identity system via the computer interface, thereby rendering available to the user of the device an attribute of the bearer having a type specified by the accepted bearer policy and/or thereby rendering available to the bearer an attribute of the user of the validator device having a type specified by the accepted policy.

The sharing token and the policy, or a link to the policy, may be received by capturing an image of a bar code provided by the bearer, in which the sharing token and the policy or policy link are embedded.

The bearer may be a user or a computer system.

Another aspect of the present invention is directed to a computer implemented method comprising performing the operations implemented by the digital identity application.

Another aspect of the present invention is directed to a computer program product comprising code stored on a computer readable storage medium and configured when executed to implement any method or digital identity application disclosed herein. Brief Description of Figures

For a better understanding of the present invention, and to show how embodiments of the same may be carried into effect, reference is made by way of example only to the following figures, in which:

Figure 1 shows a schematic block diagram of a digital identity system;

Figure 2 shows a signalling diagram for a method of creating a digital identity within a digital identity system;

Figure 3 shows a signalling diagram for a method of validating, to a validator, a bearer of a sharing token;

Figure 4 shows a signalling diagram for a method of anchoring attributed to identity documents in a digital identity system; and

Figure 5 shows how a payment token may be shared in the transaction of Figure 3.

The remaining figures are summarized below.

Detailed Description of Preferred Embodiments

Figure 1 shows a block diagram of a digital identity system 1 , which comprises at least one processor 114. The at least one processor 114 is configured to execute digital identity management code so as to implement various services, including an enrolment service 14a and a validation service 14b. The processor 4 has access to in-memory storage ("cache") 108, which may for example be implemented, at the hardware level, in volatile electronic storage.

The services 14a, 14b implemented by the processor 114 are accessed, by external devices 12, via a secure interface 104, such as a secure API. The secure interface 104 provides a secure (i.e. encrypted) channel(s) by which an external device 12 can communicate with the services 14a, 14b securely. The external device 12 can be any device desiring to make use of the services 14a, 14b, and in the examples below is a user device operated by a user. Examples of such user devices include smartphones and other smart devices, tablets, laptop/desktop computer devices etc. The data stores are implemented at the hardware level in non-volatile electronic storage.

Four data stores of the digital identity system 1 are shown: a first data store 24 ("secure store"), a second data store 33, a third data store 34 ("published data store"), and a fourth data store 31 ("master receipt book"). Data held at an addressable memory location in the published data store 34 is accessible via a public interface 106, for example using a link (e.g. URI, URL etc.) to that memory location. That is not to say that the information held in the published data store 34 is freely available to the public, as the data held therein and/or the links to it are encrypted in the manner described below.

The digital identity system 1 also comprises a secure, encryption key generator 102 ("user key generator"), the functionality of which is described later.

The purpose of the various data stores 24, 3 , 33, 34 within the digital identity system 1 is described in further to detail below. Suffice it to say that user data is held on behalf of users of the digital identify system 1 in the secure store 24. Each piece of user data is encrypted using an encryption keys ("user keys", generated by the user key generator 102) that are held only by the user himself, i.e. which are not stored within the digital identity system 1 itself. Each piece of user data is stored as the value of a database key-value pair of the secure store 24. The database key for that key-value pair is randomly generated upon creation, and is held only by the user himself, i.e. it is not associated with the user anywhere within the digital identity system 1. To gain access to this piece of user data, the user must therefore provide both its database key (so it can be located in the secure store 24) and his user key (so it can be decrypted once located). This provides a highly secure mechanism for the storage of user data within the digital identity system 1. The set of user data that is held in the secure store 24 for a given user constitutes a digital identity of the user as that term is used herein. In the following, each piece of user data is an attribute of that user, against which one or more documents or other verifiable information sources may be anchored (see below) such as surname, first name(s), date of birth, facial image ("selfie"), address etc. Thus a user's digital identity is the one or more of his attributes that are held in the secure store 24. Each of these attributes may be anchored to one or more respective identity documents or other verifiable information sources, as described later. That is, each attribute may be anchored to a different set of document(s).

A core function of the digital identity system 1 is to provide a mechanism by which users can validate themselves to one another. In high level terms, when two user's wish to validate each other, each user authorizes the digital identity system 1 to share one or more of their stored attributes with the other user. Because each user can see that the shared information is coming from the digital identity system 1 , they can trust it to the extent that they trust the digital identity system 1. This function is provided without the user ever having to share his user key or the database keys to his attributes with anyone, thus providing convenient but secure data sharing.

To enable this, the digital identity system 1 provides a user with a sharing token on request, which is bound to one or more of the user's stored attributes (as specified by the requesting user himself). Once obtained, the user can present this sharing token to another user of the digital identity system 1 to allow the other user access to his data that is bound to the sharing token (and only that data). In this context, the user who obtains and presents the sharing token is referred to the "bearer" and the other user the "validator", although in fact the system is equipped to provide not only the information needed to allow the validator to validate the bearer but can also provide the information needed to allow the bearer to validate the validator in the same transaction. To obtain the sharing token, the user provides to digital identity system 1 in an electronic sharing token request message his user key (in an encrypted form) along with the database key(s) of the attributes he wishes to be bound to the sharing token, and thus rendered available to a validator who subsequently receives the sharing token from the bearer.

The sharing token is unique to each sharing token request. A user can request as many sharing tokens as he likes, and specifies each time which of his attributes he wants bound to that sharing token, which provides a flexible sharing mechanism . Each sharing token is bound to a fixed set of attribute(s), which is specified entirely by the token request such that the user has complete control over what data he makes available with that token.

Provided the sharing token request is determined by the digital identity system 1 to be legitimate, the sharing token is generated and issued to the bearer. At least the user key and database key(s) of sharing token request are cached, i.e. temporarily stored in the cache 108, in a secure manner, in association with the sharing token, thereby binding the sharing token to the bearer attribute(s) identified in the request. Upon later presentation of the sharing token to the digital identity system 1 by a validator, the digital identity system can use the cached database key(s) and user key to locate and decrypt the bearer attribute(s) to which it is bound. Once located and decrypted, the digital identity system publishes them, i.e. stores them at an addressable memory location in the published data store 34, and provides the validator with a link to this memory location. Using this link, the validator is able to access the published attribute(s) and is thus able to access them in order to validate the bearer.

The cached request may be permanently deleted from the cache 108 after a desired duration and/or in response to presentation of the sharing token (in which case the sharing token can only be used once). Alternatively, the bearer attribute's may be decrypted when the request is received, encrypted with the sharing token and cached in association with the sharing token in place of the request. Figure 2 shows an example method by which a user of a device can create a digital identity for himself within the digital identity system 1.

At step S202a, the user uses his device 12 to capture a set of N attributes {a2,...,aN}, where N>1 , from an identity document 202, such as a passport, driving licence, national identity document etc. These may for example be captured using a camera of the device 4 or from an NFC chip embedded in the document, or a combination of both. At step S202b, the user captures using the camera of the device 12 an image of his face, i.e. his selfie, which is also an attribute of the user denoted a1 by convention herein.

At step S204, the user transmits to the enrolment service 14a of the digital identity system 1 an electronic identity creation request comprising the set of attributes {a1 , a2,...,aN}, denoted {a} for convenience below. That is, the se!fie a1 and the additional attribute(s) captured from the document 202.

In response to the enrolment request, the enrolment service 14a generates (S206) a user key Uk for the user. The user key Uk is encrypted with a device key Dk for the device 12, wherein Dk(Uk) denotes a version of Uk encrypted with Dk. To generate the user key Uk, the enrolment service 14a inputs the device key Dk to the user key generator 102. To provide optimum security, the user key generator 02 can be implemented as a dedicated, hardware security model of the system, e.g. in accordance with the FIPS 14-2 standard. In response to receiving the device key Dk, the user key generator 102 generates the user key Uk and outputs only the encrypted version of it Dk(Uk) to the enrolment service 14a. The unencrypted version Uk is never rendered directly accessible by the user key generator 102. At step S208a, the enrolment service 14a uses the device key Dk to decrypt the encrypted version of the user key Uk, and uses the unencrypted version of the user key Uk to encrypt each of the attributes a1 ,...aN. The user key Uk may be used directly to encrypt the attributes. Alternatively, each attribute may be encrypted with a key unique to that attributr ("Item key/attribute key" Ik); in this case, the item key Ik is unencrypted with the user key Uk. The encrypted item key Uk(lk) is held in the identity system 1 , in a manner such that the user can send a message to the identity system which comprises Dk(Uk) and identifies where a given one of their attributes a is stored, and also where the item key Uk(lk) for that attribute is stored. The device key Dk is used to decrypt Dk(Uk), Uk is used to decrypt Uk(lk), and Ik is used to decrypt the identified attribute lk(a).

Note that them terminology "data encrypted with a key" is not limited to direct encryption of that data with that key, an also covers, for example, a situation where the data is directly encrypted with a a different key, and the different key is encrypted directly with that key (among others).

A respective entry 24(1 ),...,24(N) is created in the secure store 24 for each of the attributes a1 ,...,aN. Each entry is a key-value pair, whose value is the encrypted version of that attribute, denoted Uk(a1 ) Uk(aN), and whose database key

Ka1 ,...,KaN of is a randomly generated sequence. The database key is needed to locate that key-value pair in the database. Below, {Ka} is used to denote the set of database keys for the set of attributes {a}. Alternatively {Ka} may comprise, for each attribute, the user massage may comprise at least one respective pointer (or other data identifying where the relevant target data is stored). The pointer(s) for that attribute may identity both where the encrypted attribute lk(a) is held, and where the encrypted item key Uk(lk) for that attribute is held.

At step S208b, the enrolment service responds to the enrolment request by transmitting an electronic response message to a network address associated with the device 12. The response comprises the encrypted version of the user key Dk(Uk), the set of database keys {Ka} and a credential c. Once the request has been sent, the set of database keys {Ka} is purged from the digital identity system 1. This means that the entries 21 (1 ),...21 (N) are not associated with the user anywhere in the digital identify system 1 ; the only association that exists between those entries and the user arises by virtue of the fact that the user holds the set of database keys {Ka}.

The credential is a one-time only use credential for the user that is bound to his device 12 and a user identifier ulD of the user. At step S208c, the enrolment service 14a stores in the second data store 33 an identifier dID of the device 12, in association with the credential c and a state of the credential. The credential is in a valid state. The state subsequently changes to either "used" or "expired", upon use or if it is not used within a certain duration form its creation. The user ulD is also stored in association with the device identifier dID, and is thereby associated in the digital identify system 1 with the credential c. By virtue of these associations, the credential is bound to both the user and the device 12.

In this example, the user identifier ulD comprises image data of the selfie captured at step S202b, which is some embodiments may also be encrypted with the user key Uk. Herein, the term image data of an image (or sequence of images) is used to mean the image itself or selective information extracted from the image(s), such as a local binary pattern (LBP) generated from the image(s) or a set of parameters generated by training a machine learning model (ML) using the image(s) themselves or information extracted from them, e.g. an ML model may be trained using LBPs which have been extracted from the original image(s).

Such selfie image data is one example of what is referred to herein as a biometric template of the user. Alternative biometric templates include image data of a fingerprint image, retinal image, or an image capturing some other suitable biometric feature of the user. In general, the user identifier ulD may comprise any such biometric template(s) and/or a non-biometric identifier such as a secret(s) known only to the user. The information embodied in the user identifier ulD is voluntarily made available by the enrolling user during enrolment, on the understanding that it is only being stored at the digital identity system 1 to prevent others from being able to gain access to their stored attributes.

The device key Dk itself is also stored in the second store 33, in association with a hash (e.g. HMAC) of Dk(Uk). The hash of an input value means an output value obtained by applying a hash function, such as an HMAC function, to the input value. The advantage of a hash is that it is impossible to recover the original input value from the output value alone. In the present disclosure, this property is exploited by using the hash H(Dk(Uk)) as an index for Dk. This allows Dk to be stored in association with Dk(Uk) without having to store Dk(Uk) at the digital identity system 1 itelf (as noted above, Dk(Uk) is held only by the user). This allows Dk to be located when (and only when) the user device subsequently presents Dk(Uk) to the digital identity system, by re-hashing Dk(Uk) and using the result to locate Dk.

Figure 3 shows a method by which a bearer, using a bearer device 12, can validate themselves to a validator using a validator device 12v. At the start of the method, each has the following:

· a currently-valid one-time use credential - cB and cV respectively - bound to himself and his device;

• a set of one or more attribute keys - {KaB} and {KaV} respectively - for a set of one or more attributes ({aB}, {aV}) held in the secure store 24 encrypted with their respective user keys (UkB, uKV); and

· a version of his user key (UkB, UkV) encrypted with his device's device key (DkB, DkV) - DkB(UkB) and (DkV(UkV) respectively.

The bearer and the validator can obtain these by enrolling with the digital identity system 1 using their respective devices 12b, 12b according to the method of figure 2. The method has two stages: a first stage, in which the bearer obtains a sharing token S of the kind described above; and a second stage in which he presents the sharing token S to the validator, who in turn presents it to the digital identity system 1. At step S302, the bearer causes an electronic sharing token request message "Req" to be transmitted from his device 12b to the validation service 14b. The sharing token request comprises the following:

• the encrypted user key DkB(UkB);

• the bearer's credential cB;

· an identifier bID of the bearer.

The request Req also comprises a bearer policy pB. The bearer policy pB is defined by the bearer using his device 12b, and specifies one or more types of attribute types that he is willing to share. For example, the bearer specify, as a minimum, that he is willing to share a selfie and, optionally, that he is also willing to share his name and/or date of birth etc. To enable the sharing of these attributes, the request also comprises the set of database key(s) {KaB} for the identified attributes(s), so that they can be located in the secure store 24. Either policy may also specify a time for which the sharing token Sk is valid, after which it expires. The request Req also comprises a validator policy pV, which is also defined by the bearer. The bearer-defined validator policy pV specifies one or more types of attribute which the bearer expects the validator to share in return. The validator is only granted access to those bearer attribute(s) as defined the bearer policy pB if he grants the bearer access to his own attributes as defined by the validator policy pV. For example, by setting the bearer and validator policies pB, PV accordingly, the bearer may denote a willingness to grant the validator access to his selfie, name and date of birth provided the validator grants the bearer access to his own selfie.

The validation service receives the request Req from the bearer device 12b, and validates the received bearer credential cB in response. That is, it determined whether the credential exists in the second store 33, and if so that its state is valid. If the credential is valid, the validation device 14b compares:

• the bearer device 12b with the device identifier dIDB bound to the bearer's credential cB in the second data store 33 (i.e. corresponding to dID in figure 2); and

• the bearer identifier bID with the identifier of the bearer bound to the bearer's credential cB in the second data store 33 (i.e. corresponding to ulD in figure

2).

The bearer identifier bID included in the request Req can take any suitable form that allows this comparison to take place. For example, the bearer may capture a new selfie at the start of the process, and the bearer identifier bID may comprise image data of the new selfie. Preferably, the bearer identifier bID generated by selectively extracting limited amount of information form the new selfie, i.e. only as much as is necessary, as this reduces the bandwidth needed to transmit it. For example, the bearer identifier bID may be an LBP generated from the new selfie.

The validation service 14b changes the state of the bearer credential cB in the second data store 33 to used and generates a fresh, one-time only use credential cB' for the bearer (S304a). The fresh bearer credential cB' is generated in bound to the bearer device identifier dIDB (and thus to the bearer himself due to the association created between ulD and dID at enrolment - see figure 2), and has a state that is initially valid.

Provided the device and the bearer ID do indeed match the corresponding identifiers held in the second data store 33, the validation service 14b generates a sharing token S as requested together with a sharing encryption key Sk. A response comprising the fresh bearer credential cB', the sharing token S and the sharing key Sk (or a link to a location at which the sharing key Sk is stored) is transmitted to a network address associated with the bearer S304b. For added security, the request may be sent out of band, for example by pushing it to a network address for the bearer device 12b that has been pre-registered with the digital identity system 1. In any event, the request is made available to the bearer device 12b.

A copy of at least part request Req is encrypted with the sharing key Sk by the validation service 14b, and cached at the digital identity system, i.e. stored in the cache 108, in association with the sharing token S (S304c). As will be apparent in view of the following, not all of the data in the request needs to be cached, and in some embodiments only the data that is needed later is encrypted and cached. For example, in some cases, it is sufficient to encrypt and cache only the encrypted bearer key DkB(UkB). In this described below, additional security is provided by also encrypting and caching the bearer and validator policies pB, pV defined by the bearer. For reasons that will become apparent, hashes (e.g. HMAC) of the fresh bearer credential H(cB') and the now-used credential H(cB) are also cached in association with the session token.

In the second stage of the method, at step S306, the bearer presents the sharing token S to the validator - together with the sharing key Sk, the bearer policy pB and the validator policy pV - to the validator. Preferably, S, Sk, pB and pV are encoded in a bar code that is displayed on a display of the bearer device 2b, so that the validator device 12v can capture an image of the bar code and extract these elements from it. In many cases, it will be possible to encode all of this information in a three-dimensional bar code (e.g. a "QR code"). If not, a link to at least some of this information may be encoded int he bar code instead (e.g. a link to a memory location at which at least one of Sk, pB, and pV is stored).

Preferably, the bearer and validator policies pB and pV are rendered on a display of the validator device 12v, so that the validator can see (i) the attribute(s) of the bearer that the bearer is willing to share and (ii) the attribute(s) of the validator that the validator must share in return. Assuming the validator is happy to proceed on this basis, at step S308 he causes a validation message to be sent to the validation service 14b. The validation message comprises the following: the sharing token S;

the sharing key Sk;

both of the policies pB and pV;

the set of database key(s) {KaV} that is needed for the digital identify system 1 to be able to locate, in the secure store 24, the attribute(s) of the validator that are specified by the bearer-defined validator policy pV;

the validator's credential cV;

the encrypted version of the validator's user key DkV(UkV); and

an identifier of the validator vID, for comparison with the corresponding validator credential bound to his credential cV (i.e. corresponding to ulD in figure 2).

The validation service 14a validates the validator credential cV in the same manner as described above. If the validator credential is valid, the method proceeds as it did for the bearer following step S302, by validation service 14b comparing:

• the validator device 12v with the device identifier dIDV bound to the validator credential cV (i.e. corresponding to dID in figure 2); and

• the received validator identifier vID with the corresponding identifier of the

validator that is bound to dIDV (i.e. corresponding to dID in figure 2).

At step S310a, the validation service 14b changes the state of the validator credential in the second data store 33 to used, generates a fresh, one-time only use credential for the validator cV, which it binds to the validator device identifier dIDv with an initially valid state. Provided the validator and validator device identifiers do indeed match those bound to the validator credential cV, at step S310a, the validation service 14b proceeds as follows.

At step S310b, the validation service 14b uses the sharing token S received from the validator to locate the cached copy of the request Sk(Req) received previously from the bearer, descripts it using the sharing key Sk received from the validator and thereby obtains the copies of the bearer and validator policies pB and pV as received from the bearer. It compares these with the bearer and validator policies pB and pV received from the validator at step S308. Provided each policy received from the validator matched its cached counterpart, the method proceeds as follows.

At step S310c the validation service 14b uses the set of database key(s) {KaB} of the bearer, contained in the cached and now decrypted request Req, to locate the corresponding bearer attribute(s) in the secure store 24. It also computes the hash of DkB(UkB) contained in the decrypted request, uses this to locate DkB in the second data store 33, decrypts DkB(UkB) using the located DkB, and uses UkB to decrypt the bearer attribute(s) located using {KaB}. The set of decrypted bearer attribute(s), denoted {aB}, is published by storing it at an addressable memory location in the published data store 34.

The validation service 14b also performs equivalent operations (S310d) for the validator, i.e. it uses the set of database key(s) {KaV} of the validator, as received at step S308, to locate the corresponding validator attribute(s) in the secure store 24. It also computes the hash of DkV(UkV) as received at step S308, uses this to locate DkV in the second data store 33, decrypts DkV(UkV) using the located DkV, and uses UkV to decrypt the validator attribute(s) located using {KaV}. The set of decrypted validator attribute(s), denoted {aV}, is published in the same manner i.e. by storing it at an addressable memory location in the published data store 34. Once the attributes have been published, the validation service:

• transmits (S312a), to a network address associated with the validator device 12v: a bearer receipt 32v, and the fresh validator credential cV".

• transmits (S312b), to the network address associated with the bearer device 12b, a bearer receipt 32b.

Again, these may be transmitted out of band in the manner described above. Each of the receipts 32b, 32v comprises a respective copy of a transaction key Tk. The validator receipt 32v also comprises a link, such as a URI, to the addressable memory location in the published data store 34 to which the bearer's attribute(s) {aB} have been published, denoted URI{aB}, thereby enabling the validator device 12v to render them available to the validator. The bearer receipt 32b also comprises a link, such as a URI, to the addressable memory location in the published data store to which the validator's attribute(s) {aV} have been published, denoted URI{aV} so that the bearer device 12b can render them available to the bearer. Although not shown in figure 3, the bearer and validator receipts 32b, 32v also comprise the links URI{aB} and URI{aV} such that the bearer and the validator can also see what has just been rendered available to the other party. The URI's URI{aB} and URI{aV} and/or the published attributes themselves {aB} and {aV} (i.e. the versions held in the published data store 34) are encrypted using the transaction key Tk, such that they can only be accessed by the bearer and validator themselves.

The validation service 14b also generates (S312c) a master receipt 32m in the master receipt book 31 . The master receipt comprises also comprises both of the links URI{aB} and URI{aV} whcih may be encrypted using the transaction key Kt (particularly if the published attributes themselves are not), and in addition

comprises:

• the hash (e.g. HMAC) of the fresh bearer credential H(cB'); and

• a hash (e.g. HMAC) of the fresh validator credential H(cV');

• the hash of the used bearer credential H(cB) - also encrypted with Kt; and

• a hash of the now-use validator credential H(cV) - also encrypted with Kt. Each of the hashes H(cB'), H(cV') functions as an index, in that the master receipt 32m can be located using cB' or cV even after they have been used or expired. Further details of the master receipt are given below. Figure 4 shows how a user's attributes may be anchored to identity documents (or other verifiable information sources), such as a driving licenses and passports. The top half of figure 4 illustrates further details of how the user's attributes may be stored in the secure store 24. As shown, each of the attributes may be stored in association with any number of anchor identifiers 406 (including zero - not ever attribute needs to be anchored to a document; for example the selfie a1 is not anchored to any document in this example), and is thereby anchored to the identified document(s). The anchor identifier need not identify the document individually (though neither is that excluded) - it is sufficient for them to simply indicate its type e.g. "passport", "driving license", "utility bill" etc.

As indicated, different attributes may be implemented to different documents, and different numbers of documents. An attribute is only anchored to a document where that document evidences that attribute. For example, in figure 1 , the user's surname a2, first name a3 and date of birth a4 are all anchored to the user's passport because these attributes appear on the user's passport and this has been verified by the digital identify system 1. For some attributes, it may be a prerequisite that they are anchored to at least one document on enrolment. Figure 4 shows how a new anchoring document 202N may be added to existing attributes. At step S402, a set of one or more attributes {a^*} is extracted from the new document 202N (driving license in this example), which is transmitted to the enrolment server 14a (S404) along with the encrypted user key Dk(Uk), an identifier of the user ulD to be compared with that held at the system 1 and the user's current credential c. At step S406, the enrolment server 14a compares the newly-captured attributes {a^*} with the attributes {a} held at the system to the extent that such a comparison is possible. For example, the name and date of birth on the driving license 202N should match the user's passport. If any of the relevant attributes do not match, the system generates an error message (S408). If attributes do match, the additional anchoring document is associated within the secure store 24 with the attributes to which it relates i.e.

those attributes that are evidenced by that document (S410a). A fresh credential is issued to the user also (S410c). An additional function provided by the digital identity system 1 is referred to herein as the "remember me" function. Within the digital identity system 1 , each of the users is associated with a unique, randomized code (e.g. unique number or other character string), which may be derived from his user key Uk, e.g. it may be derived from Dk(Uk), (which is itself randomly generated). Alternatively the composite code may be generated from the users' attributes, for example by hashing them. Whenever two users interact in the manner described above, the digital identity system combines their unique codes to generate a composite code, which it provides to at least one, and preferably both, of those users. So, in the transaction of figure 3, the bearer and the validator each receive, at steps S312b, S312a, a composite code generated by combining their individual codes respectively. The composite code is such that neither of the codes from which it is generated can be recovered from the composite code alone. The composite code is unique to that pair of users. The individual codes are static as is the mechanism by which they are combined. Therefore, whenever those two users interact with one another again in the future, each receives the same composite code and therefore knows that he is interacting with the same user as before, without the user's ever gaining access to each other's individual codes. Preferably two such composite codes are generated - one for each user, that is unique both to that user and to that pair of users. That is, a different composite code for each of the users. The composite code for a given user is only meaningful to that user, i.e. only that user can use it to determine when they are interacting the other user again (the code is meaningless to any other user of the system, including the other user in the pair).

Attributes of the kind described above, i.e. attributes demonstrating some aspect of a user's identity that has been verified by the digital identity system (e.g. based on data captured from an identity document), and which can be used to assert that aspect of the user's identity to another entity, are referred to as "identity attributes" herein. Identity attributes can identify a user by name, face (or other biometric), but this is not a requirement, and identity attributes can be anonymous, i.e. proving some aspect of a user's identity whilst still keeping other aspects of the user's identity hidden.

Examples of anonymous, identity attributes inlcude the user's age or gender.

Another example of an anonymous identity attribute is the remember me ID.

Although this is not an attribute held in the secure store 24, and is managed and used differently from such attributes, it is still an identity attribute as that term is used herein and is one example of an identity attribute derived from data of a user's digital identity, rather than being comprised in the user's digital identity. The remember me ID is unique to the user and identifies the user in that sense, but is nonetheless anonymous in this sense for the reasons discussed above.

In the examples above, attributes held in the secure store 24 are selectively published in a transaction between two users of the system 1 in accordance with the applicable policy. However there are situations where this this may not be desirable for certain types of attribute held in the secure store 24. Thus the concept of a "derivation attribute" is introduced, which is an attribute that is derived from one or more of the attributes held in the secure store 24. The derivation attribute is published, to render it available to the other party in the transaction, in place of the underlying attribute(s) from which it is derived. The derivation is preferably one-way, in that it is not possible for the other entity to recover the underlying attribute or attributes from which a derivation attribute is derived.

A derivation attribute can be identified by a policy in the same way as regular attributes, such that it is clear to a user reviewing the policy that the derivation attribute is being requested.

Derivation attributes are useful in the context of electronic payment, as will now be described.

In order to provide a "digital wallet" function on top of the core identity function, "payment attributes" can also be incorporated within the digital identity system 1 in addition to the core identity attributes. A key aspect is that a paying user or other paying entity (payee) can both authorize an electronic payment to another user or entity (payee), and assert some aspect of his identity to the payee, efficiently in the same transaction. As described in further detail later, this is achieved by allowing the payee to share, in the transaction of Figure 3, a payment token attribute along with the shared identity attribute or attributes. The payee can use the payment token to effect an electronic payment from the payer to the payee; however, in order to decide whether to actually do so, he is able to verify the identity of the payee first based on the shared identity attribute(s). One means of achieving this is to allow a user to store payment card details as part of his digital identity within the digital identity system 1 , along with his identity attributes. These can for example be credit, debit or other payment card details needed to effect an electronic card payment, for example, the payment card number, also known as a primary account number (PAN); the name as it appears on the card; the card expiry date etc.

Such details are encrypted and stored in the secure store 24 as attributes in the manner described above. These "payment attributes" as they are referred to herein form part of the user's digital identity along with his identity attributes. Depending on the implementation, a set of card details can be stored within the secure store 24 as one or multiple payment attributes, (each of) which are handled in the manner described above. That is, the set of card details can be managed as a single attribute or as a set of multiple attributes within the digital identity system 1. In this respect, all references to payment attributes herein apply equally to a single payment attribute, and vice versa, unless otherwise indicated.

The secure store 24 can be a back-end store of the digital identity system 1 as above, but it can also be implemented at the user device, wherein the user's data is held at his user device securely in a way that only the digital identity system 1 can access. Where the data is held at the user device, it is still managed by the digital identity system 1 in the same way, with the digital identity system 1 retrieving the necessary data from the user device. The same anonymous mechanism is used to restrict access in the same way.

When a payee wishes to authorize a payment to another entity (payee), the payment attribute (s) are not shared with the payee (at least in certain transactions). Rather a payment token, derived from the payment attributes is published in place of the underlying payment attributes. The payment token is an example of a derivation attribute, and at least one identity attribute is published along with the payment token in the same transaction (or otherwise comprised in or indicated by the electronic message comprising the receipt 32b).

Payment tokens are known perse and provide some level of security when making electronic payments online. There are various ways of implementing tokenization in this context, and the details of tokenization are not discussed herein. Suffice it to say that it is possible to obtain, from a token provider, a payment token that can be used in place of a payment card. Accordingly, when a user wishes to authorize a payment to another entity, instead of providing his card details, he can provide a payment token to that entity instead. The entity receiving the payment token can then effect the payment by presenting the payment token back to the token provider. The payment token can be bound to an identifier of a particular merchant (or other payee), such that it is unique to and can only be used by that merchant. In current payment systems, merchants may retain such payment tokens so that they can be re-used in future transactions. Although this is convenient for the user and is generally more secure than merchants storing the underlying card details, the payment tokens are still highly sensitive. Any merchant system retaining payment tokens is a potential point of vulnerability, and as the number of merchants retaining payment tokens for any given user increases, the risk of one of that user's payment tokens being compromised (though hacking and the like) increases. Another benefit of the digital wallet function described herein is that it does not require merchants to retain payment tokens, and achieves this without compromising the level of convenience for the user. Payment attributes are instead stored centrally at the digital identity system 1 , and can be used to effect payments to multiple merchants, by issuing payment tokens to those merchants from the digital identity system 1.

It is also noted that the subject matter is not limited to payment tokens derived from cards, and the term "payment token" generally covers any token that can be exchanged as a means of authorizing payment. For example, it is anticipated that the coming years will see an increase in API-based banking, where banks provide public APIs for the purpose of transferring funds. One factor expected to drive this in Europe is the anticipated second EU Payment Services Directive (PSD2). In this context, the payment token could be a bank authentication token that can be used in conjunction with a bank API to effect a transfer. This could for example be a bank-to- bank transfer, depending on how the technology develops. In this case, the payment token could for example be derived from a user's bank details, but this is not essential, and such authentication tokens could be generated in various ways.

As another example, the payment token could be linked to a digital wallet, to authorise a payment therefrom. This could for example be a cryptocurrency transfer, such as Bitcoin, Ethereum etc. Figure 5 demonstrates how a payment token can be incorporated into the

transaction. The transaction is shown between a purchaser device 12P and a merchant system, which in ths example is embodied as a merchant device 12M. However, these steps apply generally to any transaction between a payer and a payee.

In the transaction of Figure 5 the merchant adopts the role of "bearer", and the purchaser is the "validator" according to the terminology used above. However, the primary purpose of the transaction is actually to allow the merchant to validate the purchaser in order to determine whether to accept payment. It may be beneficial for the digital identity system 1 to also provide attributes of the merchant to the purchaser in the same transaction, so that the bearer can also validate the merchant, but this is not essential.

Initially, the merchant device 12M obtains a sharing token 502 (corresponding to sharing token S in Figure 3) in accordance with steps S302 to S304c of Figure 3. The validator policy (pV) in the sharing token request (Req) that becomes bound to the sharing token S502 specifies that at least one identity attribute is sought and also that a payment attribute is sought. The validator policy pV in this context simply means the policy specifying what attributes the merchant needs the purchaser to share in order to progress. The sharing token is an example of an identity token for use in sharing identity data, as distinct from a payment token for effecting electronic payment.

At step S506 which corresponds to step S306 in Figure 3, the sharing token 502 is captured at the purchaser device 12P along with a copy of the validator policy pV (not shown in Figure 5) so that the purchaser can see what it is that the merchant device 12M is requesting. Assuming that the purchaser is willing to proceed, then at step S408 (corresponding to S308) the captured sharing token 502 is transmitted to the digital identity system along with the purchaser credential 504 and the validator policy pV. The other information described above in relation to step S308 may also be provided if appropriate.

At this point, the transaction proceeds in exactly the way described in Figure 3 in relation to the purchaser's identity attributes labelled 505 in Figure 5. In addition, however, the digital identity system 1 decrypts the user's payment attribute (labelled 506) held in the secure store 24, which it submits to a token provider 508 to obtain a payment token 410 that can be used in place of the card details 506. The user's card details or other payment attribute(s) 506 can be captured during enrolment or added later. For a payee-specific payment token, the payee credential (to which the sharing token is linked; i.e., with reference to Figure 3, the credential cB presented at step S302 in order to obtain the sharing token Sk captured by the payer at step S506) can be submitted with the payment attribute 506, and used to generate a token that is specific to the payee. That is, in this context the underlying payee credential serves as an identifier to which the payment token is bound, such that is can only be used by the payee. That is, the payee credential itself provides data that is unique to the payer for the purpose of generating the payee-specific payment token.

The payment token 410 can for example be obtained via an API of the token provider 508. Although not shown in Figure 5 the method proceeds in exactly the same way as in Figure 3 with the payment token 510 being published and retrieved using the link in the receipt 32b issued to the merchant device 12M in exactly the same way as the shared identity attribute or attributes 505. Alternatively, rather than publishing the payment token 510, it could be rendered available to the merchant device directly along with (e.g. as part of) the receipt 32b. Either way, the upshot is that the merchant device 12M receives or is able to obtain the payment token 510 and the shared identity attributes 505 at the end of the transaction of Figure 5. The purchaser's identity can then be verified at the merchant device 12M based on the shared identity attribute or attributes 505, in order to determine at the merchant device 12M whether to accept payment from the purchaser. This can be an entirely automated process performed by the merchant device 12M, or it could have a degree of manual oversight from a user of the merchant device 12M. Assuming the purchaser's identity is successfully verified at the merchant device 12M, the merchant can proceed with accepting the payment. This is done by the merchant device 12M submitting the payment token 510 back to the token provider 508, for example via a payment API provided by the token provider 508. In this example, the token provider 508 also acts as a payment processor. However, the payment could also be processed by a separate payment processing entity.

As noted, in the above example, the purchaser and merchant correspond to the validator and bearer respectively. A viable alternative is to conduct the transaction the other way round, with the purchaser in the role of bearer and the merchant as the validator. In this context, it is the purchaser device 12P that obtains a sharing token that is captured by the merchant device. The purchaser's sharing token is bound to at least one of the purchaser's identity attributes 505 and to the payment token attribute, which is derived from the card details 506. The merchant device 12M presents the captured sharing token to the digital identity system 1 along with its own credential which eventually results in the merchant device 12M receiving the payment token and identity attribute or attributes bound to the purchaser's sharing token. In this context, the purchaser device 12P could be a basic device such as an NFC or RFID chip or tag, from which the purchaser's sharing token can be captured, and which need not have internet connectivity.

There may also be circumstances in which it is viable to store the payment token 510 itself as part of the purchaser's digital identity. For example, a "global" payment token that can be used by any merchant could be stored in this way. A merchant- specific token could also be stored in this way after it has been initially created for use in later transactions with the same merchant.

This efficient coupling of payment to verified identity (e.g. verified based on an identity document) is a powerful tool that has various applications. An important use case is combatting fraud, and online fraud in particular, as set out above. The receipts in this context provide an audit trail that links historic payment to identity.

Another example use-case is to provide age verification and payment in the same transaction. In this case, the only identity attribute that needs to be shared is an age attribute of the payee (although additional identity attributes could optionally be shared as well). The age attribute could for example be an age value, a (binary) indication of whether the user's age is above or below a certain threshold (e.g. an "18+" attribute), or the user's birthday, for example. The payee receives the age or birthday attribute along with the payment token, verifies that the payee meets the necessary age requirement, and proceeds with the payment if so. A particularly useful application of this is to provide automated age-verification and payment at a self-checkout terminal, of the kind found in modern supermarkets and other retail outlets. A self-checkout terminal is a device at which a purchaser can scan and pay for goods. For regular goods, this can generally be done efficiently without any input from a shop attendant. However, at the moment, when a user is purchasing age-restricted goods, a manual age check is needed by a shop attendant before the user is allowed to proceed and make payment. This slows down the process significantly. However, with the transaction of Figure 5, the user can verify their age and provide a payment token to the self-checkout terminal (the merchant device 12M in this context) in one go. Age verification can be performed

automatically at the self-checkout terminal, and assuming the user meets the age requirement, the self-checkout terminal can proceed with the payment using the provided payment token 510. Age-verification is particularly powerful when combined with some form of biometric authentication. Various examples of this are described later, and the provision of a payment token can be incorporated into these in the manner described above. A biometric identifier, such as a facial image or fingerprint, is captured from a user and compared with a biometric of (or associated) with the digital identity that user is asserting as his own. For example, the captured biometric identifier can be compared with a biometric template that forms part of (or that is associated with) the digital identity in question. The cumulative effect is to demonstrate that the captured biometric matches a digital identity that meets the relevant age requirement, such as 18+. There are various ways this can be implemented. Various example

implementations will now be described. These use the example of a self-checkout terminal, however the description applies equally to other forms of payee system and device and is not limited to self-checkout terminals.

One way of implementing age-verification with biometric authentication is to perform the biometric authentication at the self-checkout terminal. In this case, at least two identity attributes can be provided for the user in question in the transaction by the digital identity system 1. One of these confirms that the user meets the relevant age- requirement, and the other comprises biometric data. A biometric identifier is captured from the actual user by the self-checkout terminal, for example using a camera, fingerprint sensor or other biometric sensor of the self-checkout terminal, and the captured biometric is compared to the biometric attribute received from the digital identity system 1. Based on this comparison, the self-checkout terminal can verify that the user standing in front of it is indeed the person who meets the age requirement. In a second implementation, the biometric identifier is captured at the user device instead. In this case, the user device can for example be a smartphone or similar device equipped with a camera, fingerprint sensor or other suitable biometric sensor. The captured biometric identifier, or data derived from it such as a biometric template, can be transmitted from the user device to the digital identity system 1 to allow the digital identity system 1 to perform biometric authentication. In this case, successful biometric authentication is a condition of allowing the transaction to proceed. Examples of this are described later in the section headed "Enhanced Client Authentication" and elsewhere. In this case, the digital identity system 1 will only provide, to the self-checkout terminal, the age-related attribute if the biometric authentication is successful.

In a third implementation, the biometric comparison can be performed at the user's device itself. This could be performed based on a biometric identifier captured at the user device itself. Whilst this is viable, it does require that the user's device has the necessary equipment to capture the biometric identifier. An alternative is for the biometric identifier to be captured at the self-checkout terminal in the manner of the first implementation, but for this biometric identifier to be provided to the user's device to perform the biometric comparison thereat. In this case biometric data, such as a biometric template, can be held at the user's device and compared with the captured biometric identifier received from the self-checkout terminal. This is beneficial because it does not require the user's device to be equipped with a biometric sensor. In this case, the user's device may be a basic electronic device such as an RFID or NFC chip or tag. For example, such a device could even be embedded in a bank card or other similar object (in this case, if the user's device also lacks network connectivity, the transaction can be conducted with the user's device in the role of bearer such that the user's device provides a sharing token to the self- checkout terminal to allow the transaction to take place, i.e. with the roles of the user and the self-checkout terminal reversed relative to the embodiment described with reference to Figure 5). Another benefit of this approach is that it does not require the biometric template or similar to leave the user's device, and the template can be stored and compared with the received biometric identifier in a secure environment provided on the user's device. The user's device can then provide the results of the biometric comparison to the self-checkout terminal, either directly or via the digital identity system 1 as appropriate. Another alternative is for the biometric identifier to be captured at the self-checkout terminal but transmitted to the digital identity system 1 so that the biometric comparison can be performed thereat. This is essentially the same as the biometric authentication of the second implementation, however with the biometric identity having been captured at the self-checkout terminal rather than the user's own device. In all cases, the biometric authentication must be completed successfully (i.e. the captured identifier must match the biometric data) in order to proceed with the payment and, where applicable, the user must also meet the age requirements.

The above has been described with reference to "users" of the digital identity system 1 , who are humans. It is important to note, however, that the term "user" in relation to the described digital identity system 1 means any entity that can be represented by one or more attributed, which includes non-human entities. That is the services implemented by the digital identity system 1 can be made available to any suitable entity (including humans and machines). For example, the validation method of figure 3 is described by way of example to a validator and a bearer who are both humans with devices available to them. However, the same method can equally be applied in the case that one of the bearer or the validator the device is the bearer or validator device itself, and that in general devices may be physical or virtual.

For example, the bearer or validator may be a Web server (or other content providing server), wherein the other of the bearer or the validator may be a user desiring to gain access to content provided by the Web server. In either case, the method allows the user to be validated to the Web server and the Web server validated to the user by way of the same transaction. Accordingly, all description pertaining to "user keys" and "user data" in the above applies equally to any key generated by the key generator 102 and issued to an entity (human or non-human) and any data of that entity that is held in the secure store 24 encrypted with that key on behalf of the entity respectively, wherein terms like "entity key", "entity data", "bearer key", "bearer data", "validator key", and "validator data" can apply to human and non-human entitles alike.

Each of the bearer and validator devices described above may comprise a

processor, on which a respective instance of a digital identity application is executed so as to implement the above described functionality of those devices. Generally the various services 14a, 14b implemented by the at least processor 114 of the digital identity can be implemented at any suitable manner at the hardware level. For example, each service may be implemented by a single processor, or distributed across multiple processors of the digital identity system. For example, different services may be implemented by different processors of the digital identity, the same processor(s), or with some overlap between the underlying physical processors depending on the circumstances. In general, all of the methods, systems and services described herein may be implemented by a computer system having any hardware architecture suitable for the tasks at hand. Further the various data stores referred to able can also be implemented in any suitable fashion at the hardware level, in a localized or distributed fashion. References to different data stores does not necessarily mean that those data stores are separated at the hardware level (though that is not excluded), and can for example include separation that is purely at a logical level.

The Applicant's has filed co-pending US Patent Applications 14/622527, 14/622709, 14/622549, 14/622737, 14/622740 which describe a digital identity system, in which a user can, for example, create a profile of their digital identity (referred to therein as a "uPass") based on an identity document, such as a passport, and a self-captured image of their face ("selfie"). The subject matter of these applications has been incorporated explicitly herein below, under the heading "the Original uPass System".

In the Original uPass system, in contrast to the above-described system, the bearer provides his credential cB to the validator directly. However, the Original uPass system can be modified to substitute this credential with the sharing token Sk. That is, embodiments of the present invention relate to a version of the uPass system modified to incorporate sharing tokens in this manner.

Where the bearer credential is replaced with the sharing token Sk, the fresh bearer credential is issued by the modified uPass system when the sharing token is issued (as described above), and not at the end of the validation process (as in the original uPass system).

Note that "profiles" in in the context of the Original uPass are implemented in embodiments of the present invention as a collection of one or more attributes selected by the bearer, at his device, when requesting the sharing token.

Note also that the various encryption methods described herein can be applied to data items of the Original uPass system.

Various additional aspects of the present invention are directed to the aspects of the Original uPass system set out below, modified to incorporate sharing tokens and/or in which the described encryption techniques are implemented. The Original uPass System: Summary of the Original uPass System:

According to a first aspect a digital identity system for creating a computer stored digital identity comprises: a network interface configured to send and receive electronic messages; persistent electronic storage; a profile management module configured to receive from an entity an electronic message comprising a data item, extract the data item from the electronic message and store the data item in a digital profile in the persistent electronic storage; a credential creation module configured to generate a credential for the profile and associate the credential with the digital profile; a publication module configured to publish the profile by storing a version of it to an addressable memory location; and a receipt generation module configured to automatically generate two non-matching receipts, each receipt comprising a transaction identifier, a first of the receipts comprising a link identifying the memory location to which the profile is published, a second of the receipts comprising the credential, wherein the first receipt is stored at the digital identity system and the second receipt is transmitted to an address associated with the entity. A

corresponding method is also provided.

The profile creation mechanism of the present invention provides both a receipt for internal auditing by the digital identity system, and a credential for later use by the user.

Once created, the profile can be used by the entity to assert their identity to another entity (validator) in place of a real -word identity document. The other entity is able to access the published profile to ascertain the entity's relevant details from the data item and any other data items in the profile. Preferably, presentation of the credential to the digital identity system by a presenting entity makes the published profile available to a presenting entity (in embodiments this may in fact trigger the publication). Thus the entity can provide their credential to the presenting entity as a way to assert their identity, as embodied in the profile, to the presenting entity. That is, the digital credential can be used as a substitute for a real-world identity document.

The data item may for instance be a visual image of the entity. For a human entity, this may be a photo of their face which captured from, or which is known to match, an identification photograph from a real-world identification document such as a passport or driving licence. This may be captured using a camera and/or wireless (NFC, Bluetooth etc.) technology if a suitable electronic chip is embedded in the document. The other entity can verify that the user is who they say they are by visually comparing the user's actual face with that in the published profile. Other data items such the user's name, data of birth, nationality etc. from the identity document may also be received and stored in the profile. Multiple profiles may be created for a user, which may be unique but nonetheless share some data items. For example, a basic profile may have only one data item (e.g. photo), and additional profile(s) may have the photo plus varying degrees of addition user data (name, name and date of birth, name and date of birth and nationality etc.).

By publishing version of the profiles rather than permitting direct access to the profiles, security of the profiles is preserved as the underlying profiles themselves are never visible outside of the digital identity system.

A receipt may be generated every time a transaction involving the profile takes place. Such receipts provide an audit trail, whereby historic activity by the entity is visible within the system. For example, the receipts can be used to isolate historic fraudulent activity by a human entity (user). Where the data item is a visual image of the user's face, this makes it easy to unequivocally link such activity back to an actual human. Preferably the profile is republished at every transaction to provide a "snapshot" of the profile as it was at that time, which is unaffected by future modifications. This ensures an accurate audit trail, whereby activity at any previous point in time can be accurately isolated. Preferably, the profile is published upon presentation of the credential to the digital identity system e.g. by the validator so that the profile only becomes accessible to the validator when they present the credential.

For the purposes of auditing, a master receipt comprising data of each receipt may in embodiments be generated and stored in a master receipt book at the digital identity system. That is, both the first and the master receipt may be stored separately at the digital identity system. The master receipt may comprise only part of the first receipt, for instance the link, but not the credential. In certain embodiments, however, it may comprise a hash (e.g. HMAC) of the credential. That is, a value generated by applying a cryptographic hash (e.g. HMAC) function to the credential. The hash function is irreversible, in that it is impossible to recover the credential itself from the hash of the credential. However, if the original credential is made available to the system later by the user, the hash can be re- computed from the available credential, and the resulting value can be used to locate the master receipt. This can allow, for example, lawful interception of receipts without comprising their security.

At least part of the master receipt (at least the link) and/or the published version of profile may be encrypted with the transaction identifier, in which case the master does not include the transaction identifier. That is, the transaction identifier may be used as a cryptographic key to encrypt the link and/or the published profile itself. This means that the published profile can only be accessed by the holder of the receipt comprising the transaction identifier, and cannot be accessed using the master receipt alone. Preferably the credential is a randomised one-time only use credential, which can only be used to effect a single transaction and becomes invalid thereafter. This links the credential to the creation of the profile specifically. Similar one-time use credentials will then be needed any time the entity subsequently accesses and/or modifies the profile, and or creates a new profile, so that every credentials are linked to one specific transaction.

Preferably, metadata available to a computer device sending the electronic message is included in the message. The metadata may be metadata of the device itself, e.g. a device identifier (ID) such as a serial number or MAC address of the device, or it may be related metadata such as (geo)location (e.g. GPS) data identifying a

(geo)location of the device when the message was sent. The metadata can be used to generate the credential, for example as a hash of the metadata and a random sequence (seed). This may result in a credential having a large bit size, thus a significant memory saving results from storing the "ingredients" used to create the credential at the digital identity system rather than the credential itself. A copy of the credential can then be created as and when it is needed, for instance to determine whether a credential presented to the system matches the original (access to the published profile may only be granted if this is the case). The seed and metadata may be hashed a random number of times, and the stored ingredients then include this random number as well.

Where the metadata comprises a device ID to the profile may only be granted if the credential is presented along with a matching device ID. Thus, use of the credential is restricted to that device for added security (if the user wishes to use multiple devices to assert their identify, they can request a separate credential for each device, each credential bound to the profile).

The profile may also have a confidence value allocated to it, which is indicative of the confidence the system has that the entity does indeed have the identity which they are asserting. The confidence value is preferably made available with the published profile, for instance it may be included in and published with the profile itself to the same memory location. Thus, the validator is not simply told that the entity is who or what they say they are, but is told how confident the digital identity system that that is the case. The confidence value may be an easily interpretable metric such as a value between 0 and 1 (or 0% and 100%), 0(%) representing complete uncertainty and 1 (00%) representing total certainty, though the latter is unlikely in practice. The confidence value may change over time. For instance as the user uploads more data items e.g. photos of their face ("selfies") which may in some embodiments be required to log in to the digital identity system and stored at the digital identity system each time this may assert a positive influence on the confidence value causing it to (at least in the absence of other influences) increase, provided the photos do indeed match (whereas photos for which the match is questionable may have the opposite effect). Similarly, as the entity completes additional transaction this may exert a similarly positive influence. Conversely, where the data item(s) in the digital profile are captures from, say, a real-world identify document, as the document ages this may assert a negative influence on the confidence value causing it to (at least in the absence of other influences) decrease. Many such influences may be aggregated, whereby the confidence value reflects an overall confidence. For capturing the relevant data, a second aspect provides a method of registering a digital identity comprising: capturing at a computer device a data item associated with an entity; creating an electronic message comprising the data item; transmitting the electronic message to a registration service; receiving a receipt from the registration service; extracting a credential from the receipt to render the credential available for accessing the data item for authenticating the entity; and storing the receipt in a local receipt book at a location accessible to the computer device.

In the case that the relevant data is captured from an identity document, a third aspect provides a method implemented by executing digital identity software on a processor of a user device (for example a smart device such as a smartphone or tablet) to: capture with a camera of the user device an image of the face of a user of the device; capture data from a real-world identity document (such as a driving licence or passport), the data including an identification photograph, wherein the data is captured with the camera, from an electronic transmitter embedded in the anchoring document, or a combination of both; transmit the image of the user and the captured data to a digital identify system; and receive from the digital identify system a credential for the user, wherein presentation of the credential to the digital identity system renders at least part of the captured data available to a presenting entity.

The captured data also comprises an attribute of the document, for example enough data to be able to ascertain with reasonable certainty a type of the document (e.g. driving licence, passport etc.) and possibly to be able to determine whether or not the document seems authentic.

At the system side, a fourth aspect provides a computer implemented method implemented by a digital identity system, the method comprising: receiving in an electronic message from a user device: an image of the face of a user of the user device which has been captured at the user device; and data which has been captured from a real-world identity document and which comprises an identification photograph; storing at least part of the captured data at the digital identity system in persistent electronic storage; comparing the image of the face with the identity photograph using a facial verification algorithm; only if the image of the face matches the identification photograph, generating a credential for the user and transmitting the credential to the user, wherein presentation of the credential to the digital identity system renders at least part of the stored data available to a presenting entity.

Using facial verification in this manner ensures users can only use their own identity documents as a basis for a digital identity within the system. The image of their face and/or the photograph captured from the identity document is presented to the presenting entity, which is particularly applicable when one human is identifying themselves to another human in the real-world. Where an attribute of the document is also received, generation and transmission of the credential may only take place if the attribute matches some predetermined criteria. For example, for a passport, the attribute may be characters captured from a machine readable zone (MRZ) and the condition may be that these have a valid format.

According to various aspects of the present invention, an identity is instead asserted using a digital profile. A profile may for instance be created from data captured from a real-world identity document such as a passport or driving licence, which preferably comprises an identification photograph form the document. Once created, the profile can be used by the entity to assert their identity to another entity (validator).

In another aspect, a method of authenticating a digital credential of a bearer by a validating device comprises: capturing the bearer credential by the validating device; transmitting to a validation service the bearer credential with a validator credential bound to the validating device; at the validation service, validating the bearer credential and the validation credential, and if the validator credential is valid, using the bearer credential to access a data item of a digital profile and creating an electronic message for transmission to the validating device, the electronic message indicating the data item and comprising a fresh validator credential generated by the validation service; issuing a fresh bearer credential and creating an electronic message to transmit the fresh bearer credential to an address associated with the bearer. Preferably the method also comprises the step of using the validator credential to access a data item of a digital profile associated with the validating device and creating an electronic message for transmission to the bearer, the electronic message indicating a data item for verification by the bearer. In this manner, a single transaction provides two-way authentication - not only is the validator able to authenticate the bearer using the data item from the bearer's profile, but the bearer is able to likewise validate the validator. Thus a single transaction tells both entities whether or not they should believe that the other is who or what they assert they are. This arises from the novel combination of the validator presenting both their own and the bearer's credential together, and each entity getting back a respective data item for the other entity. The data item relating to the validator is sent to the bearer by out of band signalling, for instance to a device having an address associated with the bearer credential in the digital identity system.

In another aspect a method of providing access to digital profiles held in persistent electronic storage of a digital identity system comprises: receiving from a requesting entity an electronic request message identifying a target entity; in response to the request, publishing: (i) a digital profile of the target entity by storing a version of that profile in an addressable memory location, and (ii) a digital profile of the requesting entity by storing a version of that profile in another addressable memory location; generating two non-matching receipts, each comprising a transaction identifier, a first of which comprises a link identifying the memory location to which the target entity's profile is published, the second of which comprises a link identifying the other memory location to which the requesting entity's profile is published; transmitting the first receipt to an address associated with the requesting entity; and transmitting the second receipt to an address associated with the target entity.

Each entity can validate the other based on the relevant published profile in a single transaction.

By publishing a version of the profile rather than permitting direct access to the profile, security of the profile is preserved as the underlying profile itself is never visible outside of the digital identity system.

A link, such as a Uniform Resource Indicator (URI), identifying the addressable memory location may be transmitted to the presenting device. The link may be generated from a random sequence and/or the addressable memory location may be selected based on a random sequence. Random generation of links/selection of memory addresses ensures efficient use of the memory

address/link space.

The data item may for instance be a visual image of the entity. For a human entity, this may be a photo of their face which captured from, or which is known to match, an identification photograph from a real-world identification document such as a passport or driving licence. This may be captured using a camera and/or wireless (NFC, Bluetooth etc.) technology if a suitable electronic chip is embedded in the document. The other entity can verify that the user is who they say they are by visually comparing the user's actual face with that in the published profile. Other data items such the user's name, data of birth, nationality etc. from the identity document may also be received and stored in the profile. Multiple profiles may be created for a user, which may be unique but nonetheless share some data items. For example, a basic profile may have only one data item (e.g. photo), and additional profile(s) may have the photo plus varying degrees of addition user data (name, name and date of birth, name and date of birth and nationality etc.). Preferably, metadata available to a computer device sending the electronic message is included in the message. The metadata may be metadata of the device itself, e.g. a device identifier (ID) such as a serial number or MAC address of the device, or it may be related metadata such as (geo)location (e.g. GPS) data identifying a

Where the metadata comprises a device ID to the profile may only be granted if the credential is presented along with a matching device ID. Thus, use of the credential is restricted to that device for added security (if the user wishes to use multiple devices to assert their identity, they can request a separate credential for each device, each credential bound to the profile). A receipt may be generated every time a transaction involving the profile takes place. Such receipts provide an audit trail, whereby historic activity by the entity is visible within the system. For example, the receipts can be used to isolate historic fraudulent activity by a human entity (user). Where the data item is a visual image of the user's face, this makes it easy to unequivocally link such activity back to an actual human. Preferably the profile is republished at every transaction to provide a "snapshot" of the profile as it was at that time, which is unaffected by future modifications. This ensures an accurate audit trail, whereby activity at any previous point in time can be accurately isolated. Preferably, the profile is published upon presentation of the credential to the digital identity system e.g. by the validator so that the profile only becomes accessible to the validator when they present the credential.

For the purposes of auditing, a master receipt comprising data of each receipt may in embodiments be generated and stored in a master receipt book at the digital identity system. That is, both the first and the master receipt may be stored separately at the digital identity system. The master receipt may comprise only part of the first receipt, for instance the link and the transaction identifier, but not the credential. Preferably each credential is a randomised one-time only use credential, which can only be used to effect a single transaction and becomes invalid thereafter. This links the credential to the creation of a profile specifically. Similar one-time use credentials will then be needed any time the entity subsequently accesses and/or modifies the profile, and or creates a new profile, so that every credentials are linked to one specific transaction.

The profile may also have a confidence value allocated to it, which is indicative of the confidence the system has that the entity does indeed have the identity which they are asserting. The confidence value is preferably made available with the published profile, for instance it may be included in and published with the profile itself to the same memory location. Thus, the validator is not simply told that the entity is who or what they say they are, but is told how confident the digital identity system that that is the case. The confidence value may be an easily interpretable metric such as a value between 0 and 1 (or 0% and 100%), 0(%) representing complete uncertainty and 1 (00%) representing total certainty, though the latter is unlikely in practice. The confidence value may change over time. For instance as the user uploads more data items e.g. photos of their face ("selfies") which may in some embodiments be required to log in to the digital identity system and stored at the digital identity system each time this may assert a positive influence on the confidence value causing it to (at least in the absence of other influences) increase, provided the photos do indeed match (whereas photos for which the match is questionable may have the opposite effect). Similarly, as the entity completes additional transaction this may exert a similarly positive influence. Conversely, where the data item(s) in the digital profile are captures from, say, a real-world identify document, as the document ages this may assert a negative influence on the confidence value causing it to (at least in the absence of other influences) decrease. Many such influences may be aggregated, whereby the confidence value reflects an overall confidence.

In another aspect a digital identity system comprises: an enrolment module configured to receive a data item from an enrolling device and to create in persistent electronic storage a digital profile comprising the data item; a credential creation module configured to generate a credential from a random sequence, to associate the credential with the digital profile in a database, and to transmit the credential to the enrolling device; a publication module configured, in response to later

presentation of the credential to the digital identity system, to publish the digital profile by storing a version of the digital profile in a memory location accessible to a device presenting the credential.

An entity (which may be a user of the enrolling device or the enrolling device itself) can provide their credential a presenting entity (e.g. the presenting device or user thereof) as a way to assert their identity, as embodied in the profile, to the presenting entity. That is, the digital credential and profile can be used as a substitute for a real- world identity document.

A link, such as a Uniform Resource Indicator (URI), identifying the addressable memory location may be transmitted to the presenting device. The link is generated from a random sequence and/or the addressable memory location is selected based on a random sequence. Random generation of links/selection of memory addresses ensures efficient use of the memory

address/link space. The data item may for instance be a visual image of the entity. For a human entity, this may be a photo of their face which captured from, or which is known to match, an identification photograph from a real-world identification document such as a passport or driving licence. This may be captured using a camera and/or wireless (NFC, Bluetooth etc.) technology if a suitable electronic chip is embedded in the document. The other entity can verify that the user is who they say they are by visually comparing the user's actual face with that in the published profile. Other data items such the user's name, data of birth, nationality etc. from the identity document may also be received and stored in the profile. Multiple profiles may be created for a user, which may be unique but nonetheless share some data items. For example, a basic profile may have only one data item (e.g. photo), and additional profile(s) may have the photo plus varying degrees of addition user data (name, name and date of birth, name and date of birth and nationality etc.).

A receipt may be generated every time a transaction involving the profile takes place. Such receipts provide an audit trail, whereby historic activity by the entity is visible within the system. For example, the receipts can be used to isolate historic fraudulent activity by a human entity (user). Where the data item is a visual image of the user's face, this makes it easy to unequivocally link such activity back to an actual human. Preferably the profile is republished at every transaction to provide a "snapshot" of the profile as it was at that time, which is unaffected by future modifications. This ensures an accurate audit trail, whereby activity at any previous point in time can be accurately isolated.

Preferably, the profile is published upon presentation of the credential to the digital identity system e.g. by the validator so that the profile only becomes accessible to the validator when they present the credential.

For the purposes of auditing, a master receipt comprising data of each receipt may in embodiments be generated and stored in a master receipt book at the digital identity system. That is, both the first and the master receipt may be stored separately at the digital identity system. The master receipt may comprise only part of the first receipt, for instance the link and the transaction identifier, but not the credential.

Preferably the credential is a randomised one-time only use credential, which can only be used to effect a single transaction and becomes invalid thereafter. This links the credential to the creation of the profile specifically. Similar one-time use credentials will then be needed any time the entity subsequently accesses and/or modifies the profile, and or creates a new profile, so that every credentials are linked to one specific transaction. In another aspect, a method of providing access to a digital profile comprises receiving a one-time only use credential associated with a digital profile in persistent electronic storage; validating the credential and, only if the credential is valid, publishing the profile to an addressable memory location by storing a version of it at the memory location, thereby invalidating the credential; generating a fresh one-time only use credential for the digital profile; associating the fresh credential with the digital profile; and transmitting the fresh credential to an address associated with an entity, whereby the entity can use the fresh credential once thereafter to cause the profile to be republished to a different addressable memory location.

In accordance with this other aspect, every time a current credential is presented, a new version of the profile is published and a fresh credential created.

According to various aspects of the present invention, an identity is instead asserted using a digital profile. A profile may for instance be created from data captured from a real-world identity document such as a passport or driving licence, which preferably comprises an identification photograph from the document. Once created, the profile can be used by the entity to assert their identity to a presenting entity (validator). The entity can provide the credential to the presenting entity who presents it to a digital identity computer system. Not only is the profile made available to the validator, but a confidence value associated with the profile is presented alongside.

According to another aspect a computer system comprises: electronic storage; a network interface configured to receive electronic messages; and a processor configured to execute identity management code which operates to:

receive an electronic message from the network interface, the message including at least one data item to be included in a digital profile for an entity, the data item associated with the entity an uniquely identifying the entity; extract the data item from the electronic message;

create a digital profile using the data item in the electronic storage, wherein the profile comprises the data item;

allocate a confidence value to the profile, wherein the confidence value is allocated based on at least one of a source of the electronic message and a type of the data item; and

create and transmit a credential to the entity, wherein presentation of the credential to the computer system renders a version of the digital profile and the confidence value available to a presenting entity.

The confidence value is indicative of the confidence the system has that the entity, e.g. a human or a device, does indeed have the identity which they are asserting. Thus, the validator is not simply told that the entity is who or what they say they are, but is told how confident the digital identity system that that is the case. The confidence value may be an easily interpretable metric such as a value between 0 and 1 (or 0% and 100%), 0(%) representing complete uncertainty and 1 (00%) representing total certainty, though the latter is unlikely in practice. The data item may be a visual image of the entity, which may be a user. For example, two visual images of the user may be included in the message: the first an identification photo captured from a real-world identity document; the second a photo of the user's face which they have taken with a camera ("selfie"). Facial recognition may be used to determine how close a match the two data items are, and the confidence value allocated based on the comparison to reflect this. The presenting entity is thus told the extent to which the user's faces matches whatever form of identity document hey have used to create the profile. The confidence value may change over time. For instance as the user uploads more data items e.g. selfies, which may in some embodiments be required to log in to the digital identity system and stored at the digital identity system each time, this may assert a positive influence on the confidence value causing it to (at least in the absence of other influences) increase, provided the photos do indeed match

(whereas photos for which the match is questionable may have the opposite effect). Similarly, as the entity completes additional transaction this may exert a similarly positive influence. Conversely, where the data item(s) in the digital profile are captured from, say, a real-world identify document, as the document ages this may assert a negative influence on the confidence value causing it to (at least in the absence of other influences) decrease. Many such influences may be aggregated, whereby the confidence value reflects an overall confidence.

Corresponding methods are provided, which are computer-implemented. A

computer program product comprising code stored on a computer readable storage medium configured to implement any method or system disclosed herein is also provided.

A version of the profile may be published to render it available. By publishing a version of the profile rather than permitting direct access to the profile, security of the profile is preserved as the underlying profile itself is never visible outside of the digital identity system. A link, such as a Uniform Resource Indicator (URI), identifying the addressable memory location may be transmitted to the presenting device. The link is generated from a random sequence and/or the addressable memory location is selected based on a random sequence. Random generation of links/selection of memory addresses ensures efficient use of the memory

Where the metadata comprises a device ID to the profile may only be granted if the credential is presented along with a matching device ID. Thus, use of the credential is restricted to that device for added security (if the user wishes to use multiple devices to assert their identity, they can request a separate credential for each device, each credential bound to the profile).

Preferably the credential is a randomised one-time only use credential, which can only be used to effect a single transaction and becomes invalid thereafter. This links the credential to the creation of the profile specifically. Similar one-time use credentials will then be needed any time the entity subsequently accesses and/or modifies the profile, and or creates a new profile, so that every credentials are linked to one specific transaction.

A computer program product comprising code stored on a computer readable storage medium configured to implement any method or system disclosed herein is also provided. For a better understanding of the Original uPass system and to show how the same may be carried into effect, reference will now be made by way of example to the accompanying drawings in which:

Figure A1 is a schematic diagram of the core elements of a digital identity system; Figure A1 a is schematic block diagram of the principal components of a digital identity system;

Figure A2 is an expanded schematic diagram of functional components of a digital identity system;

Figure A3a is a schematic block diagram of data items stored as part of a digital identity system;

Figure A3b is a block diagram of a database structure for a digital identity system; Figure A3c shows a master receipt book of a digital identity system;

Figure A4a is a schematic flow diagram illustrating the creation of credentials in a digital identity system;

Figure A4b is a flow diagram showing the flow conducted at a smartphone and registration service of the creation of credentials in a digital identity system;

Figure A5 illustrates standardised passport information; Figure A6 is a schematic flow diagram showing an authentication process;

Figure A6a is a flow diagram for an authentication process;

Figure A6b shows details of receipts generated during an authentication process; Figure A6c shows details of a master receipt generated during an authentication process;

Figure A6d schematically illustrates certain relationships between various receipts and master receipts that arise due to their content;

Figure A7 is a schematic flow diagram showing an authentication process for a web service;

Figures A8a (flow chart) and A8b (signalling diagram) describe a situation where a person registered with a digital identity system wishes to have a profile assigned to them by a third party;

Figures A9a (flow chart) and A9b (signalling diagram) show a case where a person not registered with a digital identity system wishes to have a profile assigned to them by a third party;

Figure A10 shows a block diagram of a user device;

Figure A11A exemplifies how a digital identity may be created;

Figures A11 B to A1 1 H exemplify use cases of a digital profile. Description of the Original uPass System

The following description discloses an identity registration and authentication system referred to as an uPass system. As a basic premise, a user of the uPass system is able to upload and register copies of their identity documents and in return they receive an anchored digital ID which can be used to verify their identity to third parties without needing to present these identity documents. They are also able to specify the nature and quantity of personal information which will be made available when doing this. Use cases for when an identity is to be registered or verified are assumed to be strongly associated with the use of mobile devices such as smartphones and tablets although the invention is not restricted to these devices. Further, registration is described which is based on identity documents which are designed to be scanned electronically, either with OCR-friendly text or with NFC-compatible embedded chips, by way of non-limiting example. It will be evident from the following that any kind of data items pertaining to identity may be utilised, and entered into the system in any appropriate manner.

Figure A1a is a schematic block diagram of the principle components of a digital identity system.

A central service (uPass) 14 stores credentials securely and manages validations. The central service can be implemented in any suitable way and requires at least one processor 1 14 executing identity management code, and electronic storage components providing secure storage. There can be multiple processors in a distributed micro processing network, or a central processing unit at a single or multiple servers. The electronic storage components can take any form and may be local or remote memory. As will be evident, the electronic storage provides both secure storage and random access writable storage 35.

A first mobile application 22 is provided for hosting on a mobile device 12. The first mobile application is for scanning data items from an identity document and transmitting them to the central service 14. A second mobile application 50 is also provided for execution by a mobile device 12, the second mobile application for requesting a validation of credentials against the storage service 14. It will be appreciated that not all mobile devices necessarily have both applications 22 and 50. For example, some mobile devices may be equipped only to scan data items and transmit them to the central service 14 whereas other devices may be capable only of performing validation of credentials. It is likely however, that most mobile devices associated with uPass users will have both applications uploaded. The mobile applications (Apps) may be downloaded from a UPass server.

A secure architecture is provided for communication between components of the system. This ensures that privacy is maintained, in particular when considering communications between mobile devices 12 associated with uPass users and the central service 14.

A confidence framework 69 is provided for assessing the degree of confidence which can be placed in a identity profile registered at the central service 14. An automated mechanism 67 is provided for performing timely trust arbitration between users via proffered credentials (for example QR codes). Each component of the system will now be described in more detail in the following. Figure A1 shows basic elements of an identity system in highly schematic form. There are two basic workflows, one relating to registration of user identity documents and the other to verification of identity (authentication).

An electronic passport 10 or other identity document (e.g. driving licence) is read by a mobile device 12 (e.g. via NFC) and registration data is passed to the uPass service 14 in a secure manner via the Internet, as described later. The uPass service stores the registration of data in one or more profiles forming part of a digital identity 28.

There are three elements in a mobile device which can be used for storage; an SD card 12a or similar removable store; the SIM-card 12b and, in some devices, an internal secure storage space 12c. Such a storage element can be used to store a credential 30 (e.g. a QR code) generated by the uPass system from a digital profile and returned to the mobile device 12. The uPass service 14 is provided by a computer system with separate endpoints (14a, 14b) for registration and verification. Partitioning of the workflow in this manner gives confidence that a fault in the registration endpoint will not necessarily compromise the verification endpoint and vice versa. End points may be physically separate computers which can communicate via a network, or virtually separate domains at the same physical location.

Figure A10 shows a block diagram of a user device 12 (e.g. a smart device such as a smartphone or tablet). The user device comprises a processor 1 104 executing digital identity software 1006, e.g. in the form of an application or "app" (uPass app/verification application), and to which is connected a camera 1 108, a wireless (e.g. NFC, Bluetooth) interface 1010 and a display 1002 for outputting visual information to a user of the device 12.

Qualification for a restricted activity

One of the most common uses of photo ID is to confirm that a person meets the minimum legal age for a particular activity they wish to perform, such as entering a nightclub or purchasing alcohol. The uPass system is particularly well-suited to such a purpose as a client verification application 50 (see Figure A1 a) executing on a smartphone or tablet can be tailored both to answer the underlying query "is this person old enough" and to provide a photo confirmation that the person presenting credentials is in fact the person these credentials belong to. In the following description, the focus is on the precision of a photo. A number of use cases are discussed later. One example use case is of a music festival which chooses to offer ticket-less entry via uPass. In this scenario an attendee (bearer) offers their credential (the credential 30 they received from the registration process) on their mobile device and the venue operator (validator) checks this against the verification endpoint of the uPass service 14 to confirm that entry may be granted. There are several ways in which the credential could be presented: a binary blob transferred by NFC; a barcode for scanning; an email address; or, some form of QR code. uPass Connect

Another use case of interest is that of authenticating login to a remote system via a local device which may lack an uPass application, removing the necessity to remember user names or passwords so long as an uPass device (such as mobile device 12) is available. In this scenario a validating device associated with an uPass scans a QR code displayed on the login form transmitted from the remote system to the local device and uses this to establish a user system. This technique can be used to establish that the owner of the uPass device is permitted to log-in, but can also allow that owner to be confident that any content they receive from the remote system carries from a valid source.

Figure A2 is a schematic block diagram of the architecture of an uPass system as functional blocks, illustrating the workflows in the system. A registrant 20 uses an app 22 on their smartphone or tablet 12 to capture details from their passport 10 (e.g. via NFC and/or camera) and combines this with a photo 18 of themselves (a "selfie") captured with the same device to produce an electronic registration message 23. This is despatched securely to the registration endpoint 14a of the uPass system 14 which performs necessary processing (facial recognition/OCR) to extract relevant data and create an account for the registrant, as described later. Upon successful completion a confirmation message is returned to their device along with an authentication token (credential) creating a link to the new "published" uPass identity profile. Contingent trust A feature of the uPass system is that a photo is provided as part of the "published" profile linked to the credential. However, the display of a photograph when a uPass credential is presented in a verification process only confirms that the registered user's claimed identity matches that of the person who registered the uPass in the first place, not that the registered identity is itself a valid and trustworthy record of the registrant's identity.

To address this an embodiment of the invention introduces the concept of contingent trust, whereby a user's identity profile has an associated profile confidence value "CV1 " n for 2,3,4 based upon the quality and source of identity documents associated with it, and its historic usage. The way this works in practice is that the multiple sources of identity data are allowed, and for each a level of trust is assigned. Responses can then be qualified where legally required. For the purpose of explaining contingent trust, in the following, it is assumed that the identity document to be ingested is an electronic passport with the option of either an NFC interaction, an OCR-quality scan or both. In practice, the digital identity rests on primary information data items such as name, age, nationality and photograph to minimise compatibility issues.

The hierarchy of contingent trust identifies five natural levels of confidence based on the manner in which the registration data enters the system:

• presented in person to a trusted agent who confirms that it matches the presenting party;

· a trusted mobile application with additional safeguards;

• a trusted website;

• submitted via registered post;

• no registration documents The first case sets a maximum confidence level for contingent trust. The exact value assigned can be determined by statistical analysis of the risks involved, but as a rule of thumb should be no higher than 95 per cent (no data should ever be considered incontrovertible). The exact number can vary depending upon the trusted agent concerned.

An uPass can become trustworthy as a result of manual verification in this manner. So "trust" is just a fixed value based on initial registration but can vary as a set of propositions regarding the registration process for each of the multiple anchoring documents.

Additional checks can be applied to improve the standing (confidence value) of an uPass such as:

• endorsements by existing uPass users;

· NFC data reads in a trusted environment;

• random solicitation of document presentation to a trusted agent;

• random direct contact via video call to confirm uPass registrant still has registration documents

Confidence of the face verification changes with time. When users sign up they do so with their face and a passport. At this point in time there may be a very low confidence that they are who they say they are (though this depends on any anchoring document(s) they provide). Thereafter, image data is captured with every face login. Every time another selfie is captured it is added to an image database. These selfies are combined into a single Face Identification Record. The key here is that they are captured over time in a variety of different lighting conditions (because they are captured on a phone or other smart device) - and when combined provide more accurate results. In embodiments, the current facial record (which could be made up of a number of the most recent selfies, e.g. a small number such as 5) with the original passport photo captured at sign up. Note that instead of full facial images data, image data may be extracted, such as a local binary pattern (LBP) or facial template. Where a trusted anchoring document such as a passport is used at sign up, the confidence value is reasonably high but can still grow over time in this manner. Confidence of the whole system also grows over time, due to other factors such as peer to peer verification. An important feature of the present system lies in the following combination of trust anchors:

a) phone;

b) se!fie;

d) peer to peer validation.

A given confidence value is represented as a fixed point variable, to which a (variable) value between e.g. 0 and 1 (0% and 100%) is assigned. User profiles and privacy

A registrant is providing personal identifying data items to allow an uPass credential to assert their identity at a later date. By its very nature this identifying data is confidential and the uPass system provides means by which it can be handled with the level of privacy which an uPass user will consider appropriate to the circumstances in which it is being used. To facilitate this an individual uPass (digital identity) has a number of profiles associated with it.

Reference will now be made to Figure A3a to explain the nature of an "uPass" or in other words a digital identity which is created for a user and which can be verified. Figure A3a shows diagrammatically the components which make up an uPass for a person 20. These components are stored in electronic storage of a suitable kind in the uPass system. For example, each user 20 can be associated with a database or part of a database attached to a unique identifier 26 which identifies components of the uPass for that person. For example, the electronic storage can take the form of a secure store as denoted by reference numeral 24 in Figure A2. Thus, each person 20 is associated with a unique identifier 26 which is associated with all components of the uPass for the user 20. The digital identity comprises a set of digital profiles 28a, 28b, 28c, 28d. Each profile comprises one or more key value pair, where the key identifies the nature of a data item which is stored in the profile, and the value identifies the data item itself. For example, the key may be "photo", and the value would be a photograph of the user. In fact, the value may be an address where a photograph is stored as a separate component of the uPass (see 18, 18'). Although shown schematically as individual blocks, the profiles can be constructed from linked lists of key/value pairs and confidence values, with each item in a list pointing to its ancestor. Each time a profile is "published" (described later), a new "head" of the list is created, incorporating modifications arising from use of the profile.

Another component of the uPass are the one or more anchoring documents which have been utilised to provide data items for the profiles. An example of an anchoring document is the passport 10. Multiple different anchoring documents may be stored.

As mentioned above, on successful registration, a confirmation message 25 is despatched from the registration service to the app on the smartphone including a credential. Each time a data item is added to a profile, or an uPass profile is utilised, a new credential is created for that profile and transmitted to the owner of the profile. These credentials are stored in association with the identifier 26 in the uPass for the person 20, and are bound to a profile. A new credential is one modification arising from "publishing" a profile... As the credentials are used for "unlocking" the profiles, they are shown as keys 30. In practice, each credential is a unique random digital string which keys into a database, described later with reference to Figure A3b.

Each user 20 is associated with one or more smart devices (such as a smartphone or a tablet), shown as 12 and 12a. Metadata about these devices is stored as part of the uPass for the user. Each time a transaction is conducted using an uPass, a pair of receipts is issued. This will be described in more detail later, but suffice it to say that an audit trail of receipts is stored in a local receipt book 31 e as part of a user's uPass. These receipts are illustrated diagrammatically by reference numeral 32e. Each enrolled device 12a, 12b has its own local receipt book on the device or on a remote server accessible to the device. A global master receipt book 32 (figure A3C) holds master receipts 31 , which relate to (individual) receipts 32e in the manner described below. Individual receipts issued to an entity which is a bearer or validator are labelled 32v and 32e herein respectively.

As part of the authentication procedure which will be described later, when a valid credential is presented to the uPass system 14, a profile will be published according to the nature of the credential which is presented. These published profiles are shown under reference numeral 34, and are illustrated diagrammatically with keyholes which represent that a key corresponding to a credential can be utilised to unlock these profiles for publication. A profile is published by being made accessible in an addressable storage location in a memory 35 (e.g. a cache) having an address bound to the credential.

A generated credential can be stored at the uPass system, which is appropriate if it is entirely random. The stored credential is compared against a presented credential, and the profile to which the credential is bound unlocked only if the stored credential matched the presented credential. However, when the credential is generated using certain "ingredients" (such as a random sequence, random number and device metadata, such as a device identifier), it is generally more efficient to store the ingredients instead as these generally have a lower bit-size than the credential itself. The ingredients can be used to generate a copy of the credential for such comparison. For example, the credential can be generated by hashing a random seed and device metadata (e.g. which is or comprises a device identifier) a random number of times - the uPass system can store the metadata, seed and random number to create another copy later.

At the time of registration three (or four) default profiles are created: • an anonymous profile 28a which asserts uniqueness of identity and presents a photo for visual inspection;

• a photo ID profile 28b which also presents the name as listed on the registration document;

· a majority profile 28c which adds date of birth to the photo ID;

• (and an optional fourth) a nationality profile 28d which add nationality to the photo ID

Additional profiles can be created for the user which allow them to have additional personal information added or present their personal information in different ways. These profiles can be attached to them by any other user as a result of a valid uPass transaction. A profile solicitation application is used to allow for an uPass user to get another user to publish a profile on their behalf. No one can create a profile on their own behalf. Note in this respect that the uPass system comprises a controller 1 16 which acts as a third party to issue uPasses based on anchoring documents.

When new personal information is entered into a profile without the support of a registration document that profile is given the lowest level of contingent trust. For example, a third party could be an employer who enters data items into a profile solicitation application for an employee. A credential is created for the employee based on information provided by the employer, the credential is bound to the profile, and provided to the employee. To improve upon the level of contingent trust, the system allows for the uPass user to have the profile validated by other uPass users, creating a web of confidence which can be inspected. This occurs each time the owner of an u ass uses his credential in a validation procedure. The web of confidence for each profile is a social graph in which each node represents a confidence anchor. These are discussed later. The level of contingent trust placed in the document will be a function of the number and quality of validations the profile receives. Reference is made to Figures A8a and A8b to describe a situation where a person wishes to have a profile assigned to them by a third party. In the particular example which is given, the person is a new employee, and the third party is his employer. The new employee wishes to have a profile assigned to him by the employer. There are many other situations however where a person may wish to have a profile assigned by a third party. In the circumstance of Figures A8a and A8b, it is assumed that both the new employee NE and the employer E are already registered in the uPass system and have active credentials. In Step S80, the new employee supplies his credential 30 NE to the employer. In Figure A8b, the new employee device is labelled 12NE, and the employer device is labelled 12E. In Step S82, the employer sends the new employee credential 30NE and his own credential 30 E to the uPass registration service 14. In addition, the employer sends in that message a profile which he has created for the new employee. The uPass service checks that the new employee and employer credentials are valid, and if so, creates a profile for the new employee based on the information provided by the employer, and finds a new credential 30"NE to that profile. That new credential is then sent (Step S84) to the new employee device. The uPass service 14 also sends a replacement credential 30" E to the employer device, because the employer has now used up his one-time only valid credential when he sought to assign a profile for the new employee.

The profile is then stored in the uPass system (Step S88). It will be appreciated that although shown in sequence, Step S84, S86 and S88 can be carried out in any order or in parallel. Figures A9a and A9b show the case where the new employee is not already registered with the uPass system. In this case, in Step S90 the new employee makes a "real world" request to the employer "Can I have an uPass?" This could be done in person, by email or text, or in any way. The employer submits to the uPass registration service 14 a document which is going to be used to anchor a profile for new employee. In addition, the employee sends his credential 30E. In this case, it may be necessary to determine the authorisations attached to that credential, and to confirm that the employer has a credential which allows him to create uPasses for a third party. Note that this is one level higher in authorisations and assigning a profile to someone who already has an uPass. The assignation of a profile does not imply any particular validity to the uPass itself. However, creation of an uPass does imply a certain validity, although of course the confidence level which is attached to the uPass can be varied depending on the issuing anchor (in this case the employer). In Step S92 the employer submits the document and his credential to the uPass registration service 14. The uPass service creates an uPass profile for the new employee, using the document as the issuing document and with a confidence level associated with the issuing anchor. A credential is bound to each profile associated with this uPass, and the credential associated with the anonymous profile is sent to the new employee as shown in Step S96. If the new employee device has not been enrolled and is not known to the uPass, some appropriate arrangements are made to supply the credential 30" to the new employee device. In Step S98 a replacement credential is issued to the employer.

Figure A2 illustrates an account service 29 which provides a means of managing an uPass, including enrolment of devices and specification of user authorisation profiles. Authorisation profiles

As outlined earlier, an uPass profile consists of personal data and a photograph which can be used together as a cohesive identity. Each uPass credential is anchored to a profile and an uPass user can have more than one credential active at any time. However, only one credential can be active at any specific time on any given device.

Each profile available for use with an uPass account must be assigned to it by a third- party Document Issuing Authority, of which the uPass system controller itself is an example. When an uPass account is created it has at least three profiles assigned to it by the uPass system: 1. an anonymous profile 28a which can be used to assert identity but reveals no information;

2. a majority (age check) profile 28b which reveals the uPass user's date of birth;

3. a name profile 28c which reveals the uPass user's name as presented on their registration documents.

Whenever credentials are transmitted to a device they are always bound to a specific profile in the database in Figure A3b and the anonymous profile is the default profile for interactions unless otherwise specified by the uPass user.

To change profile credentials the uPass user must perform an enhanced authentication with their current credential against the uPass enrolment service to acquire a list of currently available profiles for their account. This does not need to be done for every change of profile as the information might be cached locally in an uPass application, so that the list only needs to be regenerated when new profiles are attached to the uPass account or the old profiles are removed.

Once a list of profiles is available then changing between these profiles can be performed using a standard authentication with an existing credential, which is replaced with a new credential bound to the desired profile.

All changes of profile result in security logging in the uPass system. Profile structure

As shown in Figure A3a, a profile consists of a set of key value pairs. Either can be considered an arbitrary binary field. A set can be one or more key value pair. Recognisable anonymity The base on which all other profiles are constructed is the Anonymous Profile 28a which confirms that its bearer is an uPass user and provides as its data item a current photograph. When the profile is published to a third party, it allows the third party to confirm by visual inspection that the bearer of the uPass is indeed the person for whom it is valid. A profile is published in the validation procedure described later.

The idea of querying an anonymous credential to ascertain identity may seem strange, however in an embodiment of the invention the uPass system accompanies the assertion with a receipt allowing the validating party to indirectly and anonymously reference the uPass which has just been validated.

Assigned profiles

The power of an uPass lies in the ability of its owner to present different views of their identity or rights in different circumstances. To avoid abuse, several restrictions can be imposed:

1 . profiles for any uPass account can only ever be created by third parties, noting that the uPass controller 1 16 is a third party in this respect;

2. when a profile is being created it must be created for a specific uPass account;

3. the assigned profile is bound to a specific profile in the creator's account (in this way, a creator's profile becomes a confidence anchor 1 10);

4. and is assigned a characteristic tag by the creator;

5. once created the profile cannot be edited;

6. however it can be deleted or replaced by its creator;

7. and when used the creator of the profile is always announced to the validator;

8. which allows the chain of trust right back to the uPass system to be interrogated.

The characteristic tag can be used to distinguish profiles from one another. For example, each tag could call a visual indicator to be displayed on the mobile device. Profiles and privacy

Once a profile has been assigned to an uPass account the owner of that uPass account must actively choose to use the profile in a validation for it to be available to another user. That is, the credential created from that profile must cause a link to that profile to be sent to a validator. A user can have more than one profile, hence more than one credential, stored in the same or different devices, i.e. there is only one credential per device per person, [where there is more than one profile, a user can distinguish between them by the visual indicators of the characteristic tags.]

The creator of the profile may explicitly require the use of that profile when performing a validation, in which case if any other profile is used the validation will fail. This ensures that for as long as the assigned profile exists, the uPass user can only validate their identity with that profile and that use of any other profile will be rejected. This is described later in connection with uPass Connect.

There is no way for a third party to enumerate all the profiles associated with an uPass account. Profile storage

Profile information lives in two places. The underlying data is versioned and retained in the secure store 24 whilst the current state of profile data is published in a secure key-value cache 35. This is an important underlying security premise of the Upass system - third parties are not given any access information to the secure store 24 itself.

Profile publication

A profile contained in the secure store 24 is published (at a location in memory 35) whenever a credential is bound to it. The published profile has certain properties : • expiry time (and/or publication time stamp); • Photograph or a link to a photograph;

• Encrypted profile content (key/value pairs etc.);

• Random symmetric key;

• A URI resolving to the encrypted profile content;

· A URI resolving to the creator of the profile

Every time publication occurs the profile content is encrypted with a different randomly generated symmetric key 60, and then stored at a location in memory 35 accessible via a generated URI 62. Vouchsafing

Each uPass account is capable of attaching profiles to other uPass accounts, allowing people to annotate each other with nicknames and other social information as well as vouching for the reliability of that information. As such each uPass itself is an example of a Document Issuing Authority with low confidence of reliability.

When an uPass user attaches a profile to another uPass user, the attachment is anchored against an existing profile (confidence anchor 1 10) on their own uPass account.

Aside from attaching a profile to an uPass account, uPass users can vouch for the veracity of a profile attached to another account at the request of either the profile creator or the profile recipient. As the number of uPass users willing to vouch for an assigned profile increases, so too does the confidence which can be placed in the information contained in that profile.

Document issuing authorities

Vouchsafing provides a means by which uPass accounts can be annotated with profiles, however, these are potentially low-quality sources of gossip rather than anchored identity statement. An authorised Document Issuing Authority is a recognised source of high-quality identity information anchored to real-world documents. Once an uPass user becomes a Document Issuing Authority they are allowed to solicit information from an uPass user and use this to annotate uPass accounts at a higher level of confidence than that afforded by the standard vouchsafe mechanism.

Lifecycle

Whilst uPass credentials are anchored by a passport 10 they can be caused to expire when the passport expires. This requires that uPass users be advised to update their registered documents as soon as their new passport is issued to ensure continuity of service.

An eight week notice period can be provided when the registered passport is due to expire to allow for the variable turnaround time.

When support is implemented for other identity documents the situation will become more complex. Each document will contribute to the contingent trust of the uPass and whilst this is above a certain level the uPass will remain active with regular warnings to the user regarding pending and actual document expiry.

Use

The initial scenario for uPass usage revolves around face-to-face encounters where a passport or equivalent document would be used to support identity.

Whenever an uPass bearer wishes to authenticate their identity they must present a credential (e.g. a QR code) generated from a unique random identifier provided by the uPass system. The recipient of this credential is an uPass Validator who authenticates themselves to the uPass validation service each time they validate the information received from a Bearer. Following validation the Validator decides how to proceed.

Deletion uPass users may wish to delete particular profiles or their entire uPass identity and this is supported by the enrolment service. This involves the deletion of all personal data and device identifiers and the expiring of all issued keys. There may be a legal requirement to maintain the auditing metadata associated with an uPass identity for a specified period of time, so deletion may involve a deferred component.

Suspension

When an uPass user sees misuse they can report the offending user and a suspension of the account will be imposed whilst the matter is investigated. The uPass system can provide a 7-14 day uPass suspension. When suspended, an uPass should return that the uPass identity has been suspended.

Suspension cannot occur without audited intervention and an investigation into the reasons for the suspension may be performed. Mechanisms and procedures for this are outside the scope of this document but should clearly be proportional and designed to minimise or prevent malicious suspension.

Revocation

When there is the suspicion of serious misuse, an uPass may be revoked. Revocation is similar to deletion but there may be a need to record additional information about the user to prevent them from re-joining uPass within a set period of time. Expiry

At certain infrequent time periods (governed by expiration time 68) an uPass User may be asked to create a new uPass.

If all of the anchoring identity documents for an uPass user expire, this should automatically trigger a request to issue a new uPass.

Multiple u Passes

Users may have more than one uPass account at a given time however the implementation of multiple profiles within an uPass should reduce the extent to which this occurs. For example a married woman who wishes to use an uPass in both her maiden name and married names could do this with multiple profiles on a single uPass rather than needing multiple uPasses.

Device enrolment

Each account may have one or more devices 12a, 12b associated with it at any given time. To enrol new devices into an uPass account, an audited validation transaction must be performed between this device and a device which is already enrolled for the uPass user's account.

1. Take a selfie;

2. Standard credential swap between the two devices (this means the validation app 52 on one device scans in the credential 30 offered by the other device, and vice versa);

3. When a new device goes online, server asks if the credential is valid;

4. If the credential is valid then the new device is enrolled. Device re-enrolment If the uPass account has at least one other associated device with a valid credential then re-enrolment follows the process outlined above for device enrolment. uPass account recovery

If the uPass user still has possession of a device which has been enrolled then account recovery is performed the same way as device re-enrolment with invalidated credentials. Otherwise, the uPass user can re-register using any registration document associated with the account.

Device revocation

An uPass user may revoke authorisation for any device currently enrolled for their account. This will invalidate any credential they currently have associated with the revoked device.

Device revocation does not necessarily result in uPass suspension.

Two factor registration

As mentioned earlier, each digital identity has data items derived from identity documents in a registration process. When obtaining data items from registration documents, one might assume that transmitting both the NFC (near field communication) and OCR (optical character reader) -quality data would be sufficient to confirm that the passport data is valid, however the acquisition of both sources of information via the same device leaves no way to confirm that the data has not been tampered with prior to transmission. To do that a second transmission vector may be utilised preferably involving a trusted agent and/or data acquisition device, and some form of standardised registrant signature which can be audited. In one embodiment of the registration process, the registrant submits a photograph of the registrant taken with the same device used to capture registration data, time- stamped and tagged with metadata comprising device type, operating system, geolocation and network address. The same metadata will be captured for each item of registration data captured using the device.

This photograph and the associated metadata provides an audit trail which can be used to help identify fraudulent registrations. A percentage of registrations are manually checked at the time of submission to ensure a visual match between the photograph and the photographic element of the registered identity document (e.g. passport photo).

Preferably, a facial verification service 40 compares these photographs in all cases and where there is a low level of confidence that the photos depict the same person this will also be flagged up for manual visual inspection. Rather than a single static photograph, frames taken from brief video clips can be used to capture a sense of liveness. In some embodiments, only a single frame is taken as it has been found that using multiple frames does not improve the accuracy of the face verification software. Data captured by the device camera is subject to OCR processing 42 when it reaches the registration service 14a at the uPass server, to extract data items from the identity document.

A digital signature is generated on the sum of unencrypted data. Each captured data item is encrypted by encrypt block 44. The digital signature is used to annotate each separate encrypted data item before it is submitted to the registration service. These encrypted data items are decrypted by the registration service and the digital signature checked, ensuring the integrity of the entire registration submission. In one embodiment, to further strengthen integrity the distinct registration data items are transmitted to separate end points identified by the registration application 22and encrypted with separate symmetric keys. As with all symmetric keys issued by the system these are one-time pads - keys used only once and therefore known to be unique. To implement the two-factor authentication system the registrant requires a smartphone 12 with Internet access, which is capable of communicating over HTTPS and includes a camera of reasonable (say 5MP) quality. NFC capability is a useful optional extra. The registration process

The registration process will be described with reference to Figures 4a and 4b based on the use of mobile device 12 such as a smartphone or tablet with a native application. This application will acquire the necessary photos, NFC and metadata for packaging and submission to the registration service.

The registration workflow comprises the following steps:

S1/S2. Registrant 20 initiates a registration transaction by activating an icon on the smartphone 12, which creates (S2) an electronic message R1 containing a random symmetric key k1 , of at least 256-bit, to be sent over HTTPS to the uPass registration service 14a. The preferred symmetric algorithm is AES-256 operated in GCM mode.

S3/SS4 The registration service 14a sends a response R2 encrypted with the registrant's key:

1. three unique 256-bit symmetric keys k2, k3, k4;

2. three distinct round-counts.

A round-count is a positive integer which tells the client how many times to iteratively perform a function seeded with a data value of interest. In this case we use the round- count to specify how many iterations to perform when generating a SHA-2 hash value which is a defence against rainbow table attacks. This response R2 is packed in a cookie marked with the HTTP only and HSTS flags;

55. The registrant uses their device 12 to capture data items for a registration request:

1. device performs optional NFC chip read;

2. camera captures:

1 . scan of identity document;

2. photo of registrant (selfie).

56. Metadata comprising timestamp, IP address and geolocation is recorded;

57. This is then appended to each data item to be submitted along with the item count;

a digital signature DS is generated for the registration request using HMAC.

58. Each data item is encrypted with one of the symmetric keys k2, k3, k4 to create a respective BLOB;

the distinct signature is appended to each encrypted item;

the registrant agrees to the uPass Terms and Conditions of Service;

each encrypted item is despatched to a separate network endpoint EP1 , EP2,

EP3. [

59. BLOBS (registration items) are collected in the registration service 14a;

geocodes and IP addresses are checked for each data item;

if all checks pass then the registration data is processed (see Figure A5 for a digital passport format):

1. passport scan passed to OCR service to extract MRZ, photograph and signature;

2. NFC data provides DG1 , DG5 and DG7 (MRZ, photo, signature);

3. extracted photos are compared to the registrant selfie by the facial

recognition service 40. 510. If everything matches then an uPass account may be created with:

1 . an anonymous profile 28a;

2. a photo ID profile 28b;

3. a majority (age indicating) profile 28c;

4. a nationality profile (figure Aelement^**).

In some cases, only the anonymous profile 28a may suffice

511. uPass credentials are provided to the registrant application for the anonymous profile (the default profile). A credential is a random digital sequence valid for one time use only - it can be embodied as a QR code 16 for example.

The registration service 14a is supported by an in-memory cache 24 in the secure store which contains a working-set of data elements related to current active registration for transactions, including:

1. for the IP address of each active client registration

1 . device ID;

2. symmetric key;

3. registration data [k1]:

a. registration symmetric keys [k2, k3, k4]

b. encrypted registration data items received;

c. decrypted data items.

4. account creation message;

5. account credentials

For enhanced security, there may be a requirement imposed that the data is transient and must never be stored to disk.

Each service-provided key is generated by the secure store 24 which ensures that all keys issued are unique. Forging registration transactions is impossible as keys provided by the registration server are randomly generated and cannot be predicted, therefore there is no way to use the keys from one transaction to guess the keys being used by another transaction. The guarantee of uniqueness ensures that attempting to reuse a prior set of keys will trigger a security event.

Once all expected data items for registration have been received and decrypted, the decrypted passport scan is sent to OCR service 42 and the returned data is used as the basis for an account creation message. This is checked against any NFC data received to confirm that the two data sources present the same identity, and if this is the case then the embedded photographs are compared with the registrant's confirmation photograph in the facial recognition service 40 to ensure a visual resemblance.

A percentage of incoming registrations can be manually checked at this stage to ensure that the OCR and facial recognition processes are working correctly, though this is not essential.

If the registration data passes these tests then the account creation message is passed to the secure store 24 where its uniqueness is confirmed. A data store is created for the account containing identity statements, each anchored to its source document, and the three or four initial profiles 28a, 28b, 28c, 28d created for this account. Alternatively, identity statements could be achieved to the digital signature of source documents

An appropriate credential 30 is then generated for the registrant's device using the default (anonymous) profile. The credential is stored at registrant's device and allowed access to the profile. The secure store 24 now contains profile records which can be accessed using this credential.

After successful registration the device metadata, e.g. a combination of recorded device type and operating system is used to provide download links for appropriate uPass applications from the user's profile page. To satisfy some use cases where a merchant seeks verification of a user, the merchant themselves must be registered. The merchant registration process is similar to the standard user registration process, but using different primary documents.

For the UK jurisdiction a merchant might comprise any of:

• registered corporate entity;

· sole trader;

• partnership;

• registered charity;

• club;

• society.

As a merchant registrant is an organisation, not an individual, there is a requirement to make a distinction between who owns the uPass (the merchant) and who is nominated as an administrator (one or more individuals).

A graphical illustration exemplifying the registration process is shown in figure A1 1a

Confidence anchors

An important facet of the uPass system is the self-validating nature between uPass holders. That is, uPass holders may assert their confidence in each other's identity. Each uPass can act as a confidence anchor 110 for the individual profiles of other uPass users.

Internally any data item added to a profile gains a contingent trust which is a function of both the number and quality of validations performed by other uPass users to establish it. Once entered into a profile these data items can be used in other profiles as well, but where they are, the contingent trust associated with these profiles becomes that of the least trusted data item in the profile. This way there is always a degeneration from the contingent trust represented by source registration documents which can only be offset by a statistically significant number of validations by other uPass users under profiles with a high level of contingent trust.

Third-party profiles

Registration documents provide one means by which identity can be asserted with a high level of confidence. However, there are use cases where the identity which an individual might need to present does not derive from such a source but rather from their employment or membership in a particular organisation.

To allow for this an uPass can have profiles assigned to it by third parties and the contingent trust of these profiles is that mandated by the authoring party. None of the data items associated with an assigned profile is added to the set of data items available for use in creating additional profiles or modifying existing profiles, and the assigned profile can only be modified by the authoring party. To assign a profile, a third party must be an uPass user with a valid credential. He presents this credential and provided it is valid, receives a form to enter data about the new uPass profile. This is registered as before and a credential is generated and returned This can be passed to the owner of the new profile.

An assigned profile continues to exist until the authoring party cancels it, or until it passes a pre-assigned expiration date.

Social graph privacy The uPass system contains a number of social graphs which effectively pinpoint an individual in relation to employment, friends, official documentation, transactional relationships and location. Full access to these graphs is private to the uPass system. A primary exception is when an uPass user performs a validation based upon an assigned profile. In this case details are provided for the authoring party of the profile as an additional safeguard to the transacting party.

One application of the uPass system is to broker trust between two users of the uPass system, one an individual seeking to assert their identity and the other interested in using that assertion to validate eligibility for some service or interaction. This can be seen as a single transaction comprising authentication of the parties' identities.

This trust transaction requires two separate application modes, one on a user's mobile device for asserting their identity (app 50), the other on a merchant's device (app 52) for verifying assertion and then determining if the user is authorised to undertake a particular action.

To assert identity requires the presentation of an on-device credential 30 either in a visual form such as a QR code or barcode, or as a transmittable binary blob for use with NFC or similar technology. The uPass authentication app presents an appropriate credential 30 to an uPass reader 54 in app 52 which then despatches this to the authorisation service 14b for authentication. If this authentication operation is successful, the uPass reader app 52 will receive access to one or more uPass profiles and the user can then confirm his identity based on data items in the profile he can now view, such as a photo.

When a fresh credential is generated, it is bound [to an individual profile associated with the uPass user (see database in Figure A3b). When the credential is used the information in this profile then becomes available to the validating party in the trust transaction. For added security, the profile contains no linkage to the uPass user. This precaution ensures that gaining access to a specific profile does not provide a means whereby all of the profiles associated with the uPass user can be accessed. Only the information provided in the profile associated with the credential used is exposed to the other party, along with any information which they have published on the validated uPass in the form of a series of assigned profiles.

As an added safeguard issued credentials can be bound to the device's network address 64, so if the device changes network address the credential is also invalidated.

At no point is the asserting party's digital identity identifier 26 exposed. This is essential to the integrity of the system, even for casual use cases. Likewise, no personal information regarding the asserting party is revealed beyond that necessary to broker trust.

Summary of credential creation process

This process is carried out by the identity management code executed by processor 114 (or by any suitable computer mechanism) at registration of a new profile, and at each occasion the profile is used.

1 . determine the device identification number of a new device when it is registered;

2. calculate the SHA-2 HMAC of this device identification number;

3. store this device identification number securely;

4. for each credential generated:

1 . create a random salt value (preferably at least 8 bytes in length)

2. combine this with the stored device identification number to create a unique credential number;

3. perform SHA-2 hashing iteratively with the stored credential number as the seed value;

4. the number of iterations is chosen randomly within specified bounds; 5. the resulting token is the credential passed to the device.

5. a database entry is created keyed to the generated credential 30 which contains (see Figure A3b);

1 . a random reference key 60 specific to this credential;

2. a URI 62 capable of providing the profile to which the credential is

bound;

3. the network address 64 of the device for which the credential is valid;

4. a link 66 to the uPass user for which this credential was generated; 5. the expiration time 68 of the credential;

6. other metadata 70 related to the credential lifecycle

Credentials are "single use" and "restricted". Each generated credential is specific to both the device and the uPass profile. Single use credentials

A feature of the uPass system is to allow a user to present a smartphone/tablet, etc. to validate their identity. One possibility is to use as an on-device credential its device identification number. However, this has the drawback that once assigned it cannot easily be changed and also reveals information about the device which could be used by an attacker. An improved alternative is to use a key which is generated based upon the serial number using a hashing algorithm such as SHA-2 iteratively. This involves creating a hash for the serial number and then creating a sequence of salted hashes with this value as the starting point.

Only the HMAC of the initial hash value is ever stored, enabling the identity of a device to be described without knowing its precise device identification number and thereby preventing anyone with physical access to the secure store 24 from reversing the process to determine the device identification number and use this information maliciously. To capture credentials from a device an uPass application either scans a generated QR code containing the credential or receives the credentials via some other means, such as NFC, iBureau, barcode, etc. Restricted credentials

Each generated credential is specific to both a device and an uPass profile. This prevents credentials being transferred between devices and means that any given device is only able to present one profile at a time.

Credentials are generated by creating a random salt value and combining this with the device identification number. The result is then used as the initial seed value for an iteratively generated SHA-2 hash value with the number of rounds of iteration being determined at random.

Transaction receipts

Whenever a validation transaction occurs two receipts 32e are generated, one sent to the validating party (i.e. the merchant - VALIDATOR) and one to the validated party (e.g. the uPass user - BEARER). A receipt contains four pieces of information:

1 . the random reference key 60 associated with the specific credential used;

2. the profile URI 62 to which the credential presented by the other party was linked;

3. the URI of a list of all profiles currently assigned by the recipient to the other party.

4. the timestamp The random reference key 60 acts as a transaction identifier which is associated with a specific pair of receipts and thus a specific pair of credentials. When a receipt is generated the relevant profile is encrypted with the symmetric key and published to a Published Profiles Store 35 at a randomly generated URI. Both receipts generated for a transaction thus use the symmetric key to encrypt their associated profiles.

These transaction receipts provide the basis for applications to interact with an uPass as will be explained subsequently in the discussion of uPass profiles. Each device contains a receipt book 300 (Figure A1 a) which holds an arbitrary number of receipts from prior transactions. When a user wishes to prove that a transaction has occurred they can present the receipt as a QR code, etc. which contains only the random reference key 60 for the credential used. This can then be reconciled by a merchant or other uPass user with their own receipt book.

A copy of the receipt is maintained online in the master receipt book 31 which contains all receipts generated to date.

Authentication

A client device must be pre-registered and authenticate itself to perform an uPass validation for a given profile.

Standard client authentication

Each registered device contains a single one-use credential for each uPass user that it is registered to. Submitting the credential performs an implicit authentication, which is deemed to fail if the credential is unknown, expired or invalidated. There is also a small probability that a valid credential will be invalidated (as a randomised additional security check) on receipt to force an authentication failure for security purposes. An enhanced authentication can be conducted when the standard authentication interaction fails, or where the use case requires it.

Enhanced client authentication

Some transactions require a higher level of confidence than the norm. For these a full- face photo is captured and facial recognition is used to identify potentially questionable transactions. Because facial recognition is never 100% accurate standard authentication based on facial recognition failure is not prevented if credentials are otherwise valid but enhanced authentication requests are prevented.

The enhanced client authentication mode also exists to secure administrative operations and to allow an uPass user to re-authenticate after an authentication failure. The enhanced client authentication captures a photograph of the device user which is compared to the facial recognition database for the uPass user to whom the device is registered, and if the recognition fails then a security event is triggered and logged.

Credential lifecycle

Credentials have a lifecycle which involves: their creation which binds them to an uPass profile; their distribution to a specific device; and their revocation or expiration. This lifecycle is managed solely within the validation service. When a credential is created it is recorded in the secure store and tagged with the following metadata 70 to be used as part of managing its lifecycle:

• the uPass profile for which it is valid

• the time at which the credential was requested

• the time at which the credential was issued;

· the geo- and network-locations of the requesting device at time of issue; • the expiration time (if any);

• the device details for the validation causing the credential to be issued;

• whether or not the credential has been revoked. When the credential is subsequently received all of this tagging data can be checked to confirm if the credential is being used correctly. The record is then used to create auditing and security action records elsewhere in the secure store and then invalidated.

A credential may be revoked at any time. When revocation occurs the credential's record is flagged as revoked in the secure store but the record is not processed at that time. This allows the uPass system to monitor the use of revoked credentials and use the resulting metadata to assist in fraud analysis and prevention.

Once a credential is revoked or invalidated it cannot be reinstated as valid.

Garbage collection of expired and revoked credentials may occur in one of two ways:

• when a validation query occurs for the credential;

• via a background garbage collection task which reaps expired credentials. Handling invalidated credentials

When a credential has expired or been revoked its use (i.e. someone attempting to reuse an invalidated credential for a valid use) may indicate that the device to which it has been bound has been stolen or otherwise compromised. This represents a serious fraud risk.

In these circumstances we cannot issue a new credential to the device until it has been confirmed that it is still in the possession of the uPass user for whom the invalidated credential was originally created. To confirm this we treat the device as if it is a new device being enrolled for the first time, a use case covered in the section on Enrolment.

Validator authentication

The uPass validator device is built on the same principles as a standard uPass device. To perform a validation the validator device must present a valid credential for its associated uPass device. This ensures that only users of the uPass system can run queries against the uPass trust network.

The validator credential is sent as part of the request.

Bearer authentication: asserting an identity By limiting authentication to a single authorisation query rather than an ongoing transactional relationship uPass can be used to create a simple proof of identity system. More complex use cases based on event ticketing such as guest lists or digital festival passes can be built on top of this by allowing the merchant to assign a profile to an uPass user with an appropriate expiration date.

Figure A6 illustrates a bearer only authentication process.

When a bearer-only authentication occurs the uPass reader 54 will send the credentials 30 proffered by the customer 20 in a message 100 to the authorisation service 14b. The user's credentials are then tested for validity before being marked as used and a response 122 is returned to the uPass reader along with a link to a profile which holds a photograph to allow visual confirmation of identity by the merchant. Figure A6 illustrates schematically a validation in its full context where the credential 30 on a device is backed both by a series of issuing anchors 107 which indicate the quality of registration documents 10 and confidence anchors 1 10 which indicate the extent to which the profile has been vouched for by other uPass users.

Because a credential 30 is single-use and potentially restricted it is possible that when proffered it will no longer be valid. When this is the case a fresh credential 30" may be automatically generated by the service 14b and pushed (104) to the bearer's device and from there to the validator, or the uPass user may be required to re-enrol the device. The bearer authentication process is as follows.

1 . uPass reader 54 requests credentials for authentication;

2. (optional if the uPass user has multiple profiles) the uPass user selects a profile be validated (note that validation will cause a new credential to be bound to the profile and their uPass device);

3. uPass user presents credentials to uPass reader:

4. credentials are bound to an uPass profile.

5. the credentials is despatched to the authorisation service 14b;

6. if a credential has expired, then the authorisation service:

1. in the case that the uPass user has presented a valid identity:

1 . despatches a fresh credential 104 to the uPass user's registered device ;

2. sends a retry message to the uPass reader.

2. otherwise:

1 . send an authorisation failure message to the uPass

reader.

7. if the credential is valid:

1 . the uPass user's credential is invalidated;

2. send message 122 to uPass reader comprising a link to a profile with a photograph (or the photo itself?) 8. in all other circumstances the authorisation service sends an authorisation failure message.

9. new credentials are generated and transmitted respectively to each uPass device 12.

This whole process must be repeated to perform additional authorisations, each time authenticating the uPass user's credentials against a specified profile and leading to a cascade of credential publication. Figure A6a shows a validation process in which both the credential of the bearer and the credential of the validator are validated, and in which receipts are issued. This a more complete description of the bearer authentication process described above with reference to Figure A6. The user of the uPass device selects a profile. The uPass device 12 of the bearer sends the credential 30b bound to that profile to the uPass validator 52, e.g. as a QR code . The uPass validator reads the QR code, selects a profile to use and supplies the bearer credential 30b and its own credential 30v to the uPass validation service. The uPass validation confirms that the credential 30v is valid, and if so goes on to process the credential 30b. If the credential 30b is valid, it returns (message 1 12 in Figure A6) a link to the profile bound to the credential 30b to the validator 52. It also issues a new (fresh) bearer credential 30b" to the bearer device 12 and a new validator credential 30 v" to the validator 52. Each fresh credential is returned with a receipt which is denoted 32v for the validator and 32b for the bearer. The generation of the fresh credential in each case is associated with the issuance of a pair of non-matching (individual) receipts. In each pair, one receipt is sent to the bearer and comprises a link to a newly-published published profile of the validator and the fresh bearer credential for later use by the bearer, and the other receipt of the pair is returned to the validator and comprises a link to a newly- published profile of the bearer and the fresh validator credential. Thus, in the embodiment of Figure A6a, a pair of receipts is issued for the creation of the fresh credential for the validator, and a pair of receipts is issued for the fresh credential for the bearer. The two receipts 32e, 32v comprise matching transaction identifiers identifying the transaction in which they were created and tying them together. A corresponding master receipt 32 comprises the same transaction identifier (which links it to the corresponding receipt pair) and both links but not the credentials. The receipt 32v can include the link to the photograph for the bearer in the relevant profile.

At any time between transactions a user can choose to acquire credentials for a different profile. However, they can only ever have one credential on their device for a given uPass user.

Figures 6b and 6c show additional details of the receipts 32b, 32v that are generated in the validation transaction of figure A6a. Each of the receipts 32b, 32v comprises the same transaction identifier 60, which is a symmetric encryption key for the transaction. The bearer receipt 32b comprises a link 62v to the version of the validator's provide published in the validation transaction, and a confidence value 65v associated with the profile that the bearer has just presented (i.e. to which the link 63b in the validator's receipt 32v points). Similarly, the validator receipt 32v comprises a link 62b to the published version of the bearer's profile, and a confidence value 65b associated with the profile the validator has just presented (i.e. to which the link 63v in the bearer's receipt 32b points). Each of the bearer and validator receipts 32b, 32v also comprises a respective link 63b, 63v to a list of all of their profiles currently assigned to the other of the bearer and the validator. As noted above, in addition to the bearer and validator receipts 32b (i.e. C'B), 32V (i.e. C'v), a master receipt 32 is generated for the transaction, details of which are shown in figure A6c. The master receipt 32 comprises a hash (e.g. HMAC) of the fresh bearer credential 300b, i.e. H(C'B), and a hash of the fresh validator credential 300v, i.e. H(C'v), where H denotes a cryptographic hash function (e.g. HMAC) that is applied to that credential thereby generating a hash of that credential. That is, the master receipt 32 comprises hashes of both of the fresh credentials 30b", 30v" that are issued at the end of the validation transaction. The credentials 30b", 30v" cannot be obtained from the hashes 300b, 300v alone. However, the credentials 30b", 30v" issued to the bearer and validator respectively can be used later to locate the master receipt 32, even after they have been used or have expired. In other words, the hashes 300b, 300b are first and second indexes of the master receipt 32 respectively, which can be used to located it in the master receipt book 31 when (and only when) one of the credentials 30b" or 30v" is rendered available to the uPass system. The master receipt is locate by hashing the available credential to generate a search index, which will match the corresponding index of the master receipt 32. The master receipt book 31 can be implemented in any suitable manner that allows these indexes to be searched, for example as a distributed data store.

The master receipt 32 also comprises both of the links 62b, 62v to the published profiles, their associated confidence values 65b, 65v, and both of the links 63b, 63v to the profile lists - all of which are encrypted with the transaction identifier 60. Alternatively or in addition, the published versions of the profiles to which the links point may be encrypted with the transaction identifier. In embodiments, the transaction identifier 60 is not included in the master receipt 32, nor is it stored within the uPass system. Thus, the contents of the master receipt 32 can only be accessed by the holder of either of the receipts 32b, 32v in such embodiments.

The master receipt 32 may also comprises data that matches at least part of the two previous master receipts for the bearer and validator respectively - 32' and 32" in figure A6d, respectively. This data is in the form of a hash of the now-used bearer credential 302b, i.e. H(CB), and a hash of the now-used validator credential 302v, i.e. H(Cv). The hash 302b of the now-used bearer credential 30b matches the corresponding index of the earlier master receipt 32' that was generated in the transaction in which the bearer credential 30b was first issued (first earlier master receipt) and the hash 302v of the now-used validator credential 30v matches the corresponding index of the master receipt 32" that was generated in the transaction in which the validator credential 30v was first issued (second earlier master receipt). These indexes are public, in that they are not encrypted with the transaction identifier 60.These two earlier master receipts 32', 32" can thus be located using the hashes of the bearer and validator credentials 302b (i.e. H(CB)), and 302v (i.e. H(Cv)) respectively,. Because the earlier master receipts 32', 32" have been generated in the same manner as the master receipt 32, one of the public indexes of the first earlier master receipt 32' will match the H(CB) from the current master receipt 32 - that index having been generated in the earlier transaction when CB was issued to the entity who is the bearer in the current transaction (but who may have been the bearer or the validator in that earlier transaction); likewise, one of the public indexes of the second earlier master receipt 32" will match H(Cv) from the current master receipt 32 - that index having been generated in the earlier transaction when Cv was issued to the entity who is the validator in the current transaction (but who may have been the bearer or the validator in that earlier transaction). In turn, those indexes of the earlier master receipts 32', 32" relate, in the same manner as the current master receipt 32, to receipts issued to the entities in question in the earlier transactions (as do their other indexes).

These two additional hashes 320b, 302v may also be encrypted with the transaction identifier 60. This allows those earlier master receipts 32', 32" to be located in the master receipt book 31 from the current master receipt 32 only when the transaction key 60 is made available from the bearer or validator receipt 30b, 30v. Moreover, the content of the each of the earlier master receipts 32' 32", and/or the published profiles to which it links, is encrypted with its own respective transaction identifier i.e. the respective transaction identifier of the earlier transaction in which it was created (which is different from the current transaction identifier 60), and can thus only be accessed with the bearer or validator receipt created in that earlier transaction.

The master receipt 32 also comprises first and second digital signatures 304b, 304c, generated from at least a part of the earlier master respects 32', 32" respectively and/or hashes thereof. Preferably, the signatures and/or the hashes are generated from all of the data of the master receipts, including their public indexes. That is, as SIG(32') and SIG (32"). The signature can be generated using a private key known only the uPass system, and can be verified using a corresponding public key to verify the receipt is authentic. The signatures 304b, 304v are also encrypted with the transaction identifier 60. The bearer and validator receipts 30b, 30v are encrypted with keys 306b, 306c previously registered with the uPass system by the bearer and validator respectively, (a user can deposit a public or symmetric key with the service if they want to, and then the system can use it for communicating with them securely). This means that only the bearer and the validator can access their content respectively.

It's also possible to have multiple signatures in a master receipt generated by different means, and to allow a master receipt to be split into more than two receipts by including additional credentials and signatures in the master receipt. Enhanced validation

Some transactions require a higher level of confidence than the norm. For these an enhanced validation process can be adopted. 1 . The bearer sends an out of band facial image to the uPass server, accompanied with their current credential and the time that the selfie was taken.

2. The bearer sends to the validator their credential and the facial image for bearer.

3. The validator adds their credential to the message and sends this to the uPass server.

The uPass server validates the message and compares the image data which was sent from the bearer to the validator with the image data that was sent in an outer band communication between the bearer and the uPass server. If the selfie has not arrived when the validation is performed, the uPass server may compare the image data which has been sent to the validator to the bearer's previous entry in their facial image database. The image data which is sent from the bearer to the validator can be an LBP extract from the facial image. Note here that a selfie is a facial image captured by the bearer using the camera on their mobile device, for example.

Mutual authentication peer-to-peer trust

One useful feature of the uPass system lies in its ability to establish mutual trust between two parties, allowing a broader range of interactions than those permitted by the bearer authentication mode. In this case each party presents credentials to the other for authentication by the authorisation service and an ongoing transaction is established.

The advantage of a transactional model is that transactions cannot overlap, therefore any device can only be engaged in a single transaction at any one time. If a device attempts to start a new transaction the previous transaction can be automatically terminated.

When a mutual authentication occurs each party captures a credential from the other party and despatches this to the authorisation service for authentication. If both sets of credentials authenticate then a transaction is established and each party is issued a unique symmetric key which is used to encrypt their ongoing communication with the server. These keys are time-limited (for example, a limit of approximately 5 minutes) and if the transaction is ongoing will be replaced when they expire.

A transaction can remain active for an indefinite period of time, but to do so both parties must send a keep-alive message to the authentication service when their keys expire. If either party fails to provide the keep-alive message then the transaction is terminated.

As an added security measure each transaction can be tied to the specific devices used to initiate it, and to a specific profile for each party.

Once a transaction is initiated either party can test authorisation propositions against the active profile of the other party for the duration of the transaction. Anonymous authentication

The uPass system ties authentication to a specific profile (28a....28d) but leaves the uPass user in control of how much information they reveal to the other uPass users via their profile selection. It is therefore practical for two uPass users to broker trust for a given purpose without revealing any personal details to each other - only to confirm their physical appearance. To facilitate this every uPass user has an associated anonymous profile 28a.

Profile avatars

A second possibility for credentials is the use of a characteristic avatar (an image, movie clip or audio file), which is issued by the uPass system with a credential embedded in the data. Profile avatars with company logos can be used to embed a credential. The avatar image can then be submitted to a website or via NFC to a mobile device with the recipient authenticating it against the uPass system and receiving back the source data which can be used to confirm the identity of the user.

The avatar acts as a container for credentials which aside from the need for embedding and extraction are handled in exactly the same way as any other uPass credentials. Each avatar is bound to an uPass profile. In some circumstances there may be a limit on the number of avatars allowed per profile, as yet to be determined.

Web-based authentication

In the above description, it is assumed that uPass credentials are stored and read by mobile devices using proprietary applications. Another use case which needs to be addressed is that of conventional web applications running inside desktop browsers. This is referred to herein as uPass Connect and is illustrated in Figure A7.

UPASS CONNECT uPass Connect provides a protocol whereby the user of a network system wishing to login to that system can do so using their uPass credentials on a trusted device such as a phone or tablet. One use case is for websites and applications, however uPass Connect should be usable with any client/server system capable of presenting a unique token to the uPass user. In this situation there are two trust queries being performed:

• the uPass user 20 is seeking to confirm the identity of the system (web server 80) to which they are providing a credential;

• the system (web server 80) is seeking to confirm the identity of the uPass user 20.

There are actually three actors involved in this transaction as the local device 173 (e.g. a PC) being used to login to the system needs to acquire the trust which is being mediated between the uPass device 73 and the remote system 80. Server enrolment uPass Connect brokers trust between a server 80 and a client device 12. The client device 12 is already enrolled for the prospective user 20 and has a credential 30 bound to a profile. However, for the server to interact with the uPass system it needs to be enrolled as a device. This process binds (in the database of Figure A3b) an uPass profile 28 for the server operator to a credential 30 to allow interaction.

Once enrolled the server is able to create virtual devices which can then be used to manage login and registration initiated by prospective users of the server.

Virtual devices

The uPass validation transaction requires that each uPass credential is uniquely bound to both a profile and an enrolled device. Whenever a network system establishes a session by presenting a login or registration form 177 to a visiting uPass user via a client application, it needs to uniquely identify this session to the uPass system. Which introduces the need for a transient virtual device. A transient virtual device is created as part of the session establishment procedure, triggered by step 71 "I want to use URI". This device is enrolled using a standard uPass validation and assigned a unique device identifier. This device identifier needs to be unique for the uPass user providing the uPass Connect session. The same device identifier can be reused across different uPass users.

Once the virtual device has been enrolled, a credential 30 is issued to it, which is transmitted (step 72) in a webpage and forms the basis for a QR code 179. Which will be displayed in the updated webpage 177 issued after enrolment of the virtual device. The native app on the smartphone 12 can scan in this QR code and transmit it to the uPass validation server 14. Inversion of trust In the standard uPass validation scenario described in the preceding sections, a validator requests that a client (bearer) wishing to engage with them to provide an uPass credential which can then be checked against the uPass validation server. The uPass Connect system does not take this approach as there is no guarantee that the client application will be running on a device capable of soliciting a credential from the uPass user seeking to use the network service.

To get around this, the uPass validator presents the credential in visual form (such as the QR code 179) via the client application and the uPass user 20 seeking access scans this (step 73) into their own uPass-enrolled device 12. As an alternative to the QR code, the scan could be by NFC, Bluetooth, Wi-Fi, audio, or any other data transmission mechanism. This flexibility allows uPass Connect to support Internet of Things embedded use cases. In step 74, a check is performed to a URI verification service to check that the FQDN of the URI is registered (step 75), a confirmation is returned to the smartphone (step 76). An optimal additional step for enhanced security can be conducted, wherein in step 77 the device 12 sends a receiving address with the acquired token and its old token. This receiving address is used to open a back channel, step 716. The remote service confirms validity to the smartphone 12, step 716.

This scenario can play out in one of two ways. In the most common case the uPass bearer 20 is using their mobile device 12 to gain access to a web site via a browser session running on a desktop or laptop device 173 scanning the QR code displayed in the client application.

There is however a second possibility in which the uPass user wishes to connect to the website from a browser or application on the device hosting their uPass credential. Where this is the case the QR code will be transferred from the browser application to the uPass application and thence transmitted to the validation service. Once acquired, this credential (which is annotated with the URI indicating the system to which the client application is attempting to connect) is passed (step 77) to the uPass validation service, which then determines if the URI is valid and known, by looking up the credential in the database of Figure A3b. To simultaneously validate the user of the device 20, his credential is added to the message in step 77. Assuming the credentials are validated, a receipt is sent to the URI server 80 (step 78) which determines what to do (step 710) based on the validated identity presented in this receipt. A receipt is also sent (step 79) to the device 12 with details of the server hosting the URI, for display (step 712) to the user 20.

Requiring a specific profile

A server supporting uPass Connect may wish to only ever receive profiles it has assigned. This can be reflected in the credentials used by its virtual devices.

Registration completion

When an uPass user wishes to register with a service supporting uPass Connect they have the option of performing an uPass validation. This provides the server with their current profile (providing details information for a registration form) and a link back allowing a profile to be published against their uPass account.

Business case: online age verification One of the key problems uPass Connect solves is the need to certain web-based industries to restrict access to their services in response to minimum-age legislation. This applies to sites operating in the online gambling, pornography, video and general retail sectors. Site operators can require an uPass age-check profile to determine the legal eligibility of a visitor to access their content and take appropriate action based upon this. Performing this validation also creates an audit trail so that the site owners can subsequently demonstrate their compliance with the law.

Business case: virtual cookies

When a site uses uPass Connect to control access to its content, it gains the ability to annotate users' uPass accounts with site-specific profiles which can be queried on subsequent visits. These can be used to store arbitrary information and therefore have a similar role to browser-based cookies, only without the inconvenience of storing them on a user's system.

Business case: restricted site membership

Many websites enforce a paywall around their content and maintain proprietary membership lists to control access through this which necessarily also require profile systems to allow user customisation. With uPass Connect both membership access and profiles can be managed via the standard uPass mechanisms.

Business case: embarrassing services

There may be cases where the nature of the service being accessed is such that an uPass user would not want their photo shared with the service for quite legitimate reasons of personal embarrassment. Referring to Figure A2, the secure store 24 is a secured, privacy-preserving data store which contains user credentials and related metadata. It is an aim of the system design that an uPass operator should have the bare minimum access to the personal information associated with any given uPass user. If this data store is ever compromised, so potentially are the identities of all the users. Therefore the secure store is placed on a separate internal network segment isolated from the outside world with multiple layers of hardware security to ensure this. The data link between the uPass service and the store is secured at a protocol level to further reduce the risk of internal threats. Within the data store 24 are contained (see Figures 3a/3b):

• the registered identity documents 10 for each individual;

• details of their authorised mobile device 12a, 12b;

• currently issued credentials 30;

• all previously issued and now invalid credentials 30';

· identity statements and their confidence anchors 1 10;

• identity profiles 28a...2b.

This content is stored in an encrypted form.

An encrypted database also needs a search facility and this is implemented in one embodiment by storing characteristic cryptographic hashes for each indexable data item. These have the advantage of being irreversible making it impractical to use them as a means of recovering the source data in the event that the secure store is compromised, whilst at the same time having a very low probability of collision making them good index keys.

Whenever an incoming request for identity assertion is received the uPass system first checks to see if the device is authorised to make the request. If it is, then receipts will be generated for both parties which are stored in the Master Receipt Books using their provided public keys.

Facial recognition database

For each user, a separate facia! recognition database is maintained trained on that user's photos. Offline usage

The standard uPass mechanism described above are predicated on the availability of network access for both uPass bearer and uPass validator.

Credentials

An uPass credential is one-use and requires validation by the uPass validation service. Therefore credentials cannot be used reliably for offline usage.

Receipts

Receipts are statically published identifiers which always correctly resolve to a published profile and to a consumed credential.

Many offline use cases can be modelled in terms of a locally deployed cache of transaction receipts. The local database of transaction receipts is effectively an offline identity cache with visual user validation supported by a photo for each receipt.

The transaction identifier in the receipt will never change so this can be presented as a printed QR code, barcode or binary blob in an NFC tag.

It is the responsibility of the uPass validator to ensure that relevant profile data is successfully acquired before their access windows expires, and that charged items are properly accounted for during the event.

Receipt-based usage can be reconciled later via an online mechanism to provide a concrete audit trail. e-Wallet Another possible application of uPass is a digital wallet which allows a sum of money to be associated with a particular device and used to purchase goods or services. This is essentially an extension of the qualification use case which adds a transactional exchange, requiring confirmation to the vendor that a payment has been successfully made along with the actual transfer of money between the two parties.

Confidence values - vouching A transaction can be performed with the particular intent of increasing the confidence value assigned to a target entity's profile, in which a vouching entity vouches for the target entity. The vouching entity collects a credential from the target entity and presents it to the uPass system with their own credential in an electronic vouching message. The vouching entity's credential is bound to a profile of the vouching entity to which is allocated a relatively high confidence value (relative to the target's profile as bound to their credential). On the basis of that higher confidence value, the transaction causes the confidence value of the target entity's profile to be increased. Being a transaction, this uses up the vouching and target entity's one-time use credentials and fresh credentials, bound to the respective profiles, are issued accordingly.

When the target entity's profile is later made available to a validator through presentation of the target's fresh credential, the uPass system may in addition to revealing the (now higher) confidence value of the relevant profile, identify the vouching entity as the source of the high confidence value to the validator. For example, the validator may be a business, the vouching entity a well know customer of that business, and the target entity a new customer of that business. The profile may be a profile created specifically for the benefit of that business, whereby the initial low confidence value of the target's profile is indicative of the fact that the target is an unknown customer. Use Cases - figures 11 B-H

In each of the use cases of figured 1 1 B-H, a validator captures a credential from a bearer. In some cases the user is a bearer and the validator a device, in others vice versa. Sometimes both are humans. Each use case is based on a uPass transaction, in which the validator captures a bearer credential 30, and present's it to the uPass system with his/her/its own credential. Both credentials are one-time only use and bound to bearer and validator profiles respectively, which may be profiles specifically created for the sype of transaction in question. Subject to both credentials being valid, a version of the validator (resp. bearer) profile is published and a link to the published version provided in a receipt sent to the bearer (resp. validator). This uses up the credentials so fresh validator and bearer credentials are also issued in the validator and bearer's receipts respectively. A user 20 can verify their identity to an event owner (fig A11 B) by showing a valid credential 30 bound to e.g. a profile specific to the event on the display as a QR code. In this scenario, the user is the bearer. The creation of the event profile may be conditional on the user having paid an appropriate admission fee or some other predetermined admission criteria. A validator (event owner) captures the credential and presents it to the uPass system. The system publishes the relevant profile so that it is accessible to the validator. The profile may simply be a phot of the user's face 20. The validator can compare the photo to the user and thereby verify that the user 20 does indeed have a profile for the event (because they match the photo) and admit them to the event.

A credential outputted by a web page (fig A1 1c) on a separate device 1 102 can be captured by the mobile device 12 can be used to simultaneously verify the website to the user 20 of the device 12 and the user to the website. In this scenario, the user is the validator and a Web server is the bearer. The user wishes to log in on a separate device, and captures the website's credential 30 from the separate device using their mobile device 12. That is, the credential is received at the mobile device 12 from the Web server via the separate device 1 102. The user presents their own credential and the captured credential to the uPass system. Subject to both being valid, the uPass system verifies the user to the Web server (by publishing the user's relevant profile to a location accessible to the Web server and sending a receipt with a link to that location), and the Web server to the user (by publishing the relevant profile of the Web server to a locational accessible to the user device 12 and sending a receipt with a link to that location). The web site can grant access to the user accordingly, and the user can proceed safe in the knowledge that the website is genuine. Both the Web server and the user have now used up their one time credentials for their respective profiles so fresh credentials are issued with the receipts. Figure A12D shows a similar scenario, in which the website is instead accessed on the mobile device 12 directly. Here, the credential 30 (not shown in fig A12D) comes straight to the mobile device 12 from the Web server via the Internet or other network. The underlying mechanism is otherwise the same.

Figure A1 1 E shows how a user may effect a purchase form a website hosted on a Web server presented on a separate device with their mobile device 12. After capturing the website's credential, the user is required to provide additional verification by entering a PIN or scanning their fingerprint for example before the uPass app will present the captured credential and the user's own credential to the uPass system to provide additional security. Because the website has confidence the uPass system, it allows the transaction to proceed on the basis of the receipt which is issued to it. Figure A11 F shows an equivalent scenario in which the website is provided to the mobile device 12 directly, and without the additional layer of security. In both figures 1 1 E and 11 F, a key aspect is the simultaneous verification of the web Server to the user (so the user knows they are safe to purchase goods or services form the website), and the user to the Web server (so the website knows it is safe to sell to the user). As will be apparent, an equivalent use case is a real-word use case in which Web server is substituted for a human vendor operating the separate device 1 102. Figures 1 1 G (separate device) and 1 1 F (same device 12) shows how a user may use their uPAss to donate to charity. The underlying principles are the same as the purchase scenarios only here the reward reaped by the user is intangible.

Transactions - examples

A credential bound to a profile can be used once in a uPass transaction to do e.g. one of the following:

1. simply publish that profile to make it accessible to a validator;

2. modify that profile e.g. by adding a data item(s) to it;

3. create a new profile;

the profile to which the credential is bound is also published in 2 and 3, as that is an inherent part of a uPass transaction. In 2 and 3, a requesting entity may be e.g. an employer and a target entity an employee (see above), or the requesting entity may be a part of the uPass system itself e.g. the validation service 14b or uPass controller 1 16 - as an exception, the part of the uPass system may not have a profile or its own credential (though neither are excluded). Thus, in this case, only one profile may be published (the target's, sent to the part of the uPass system) and only one fresh credential may be generated (for and sent to the target). A uPass transaction can be conducted between three entities (such as bearer 20, validator 52, and validation service (authenticator) 14b), as shown in figure A12. In figure A12 F represents a function to be executed. This may be a simple validation. It may also be an operation specific to the secure store 24 as expressed by a public API. A represents an authentication wrapper for F. The bearer 20 (e.g. customer) sends their credential Cc to the validator 52 (e.g. merchant) in a first electronic message. The validator sends its own credential Cm with the bearer credential Cc with an indicator of the function F to be executed to the authenticator 14b in a second electronic message ("CmF(Cc)"). The authenticator sends CmF(Cc) with an indicator of the authentication wrapper A and its own credential Ca to the secure store 24. A set of four receipts R1 , R2, R3, R4 ({Ri}) is generated. A master receipt for the transaction is stored in the master receipt book 3 , and bearer/validator receipts 32v/32b (R2/R3) are issued to the bearer and validator 20, 52. R1 is issued to the authenticator 14b, and R4 is logged in a secure access log 1202. All of the receipts R1 , R2, R3.R4 and the master receipt share a transaction identifier which links them all together, Figure A13 shows a similar scenario, however in this case the customer communicates directly with the authenticator 14b and receives both receipts R2, R3.

Alternative biometrics:

In other embodiments, another type of biometric data (other than, or in addition to, the selfie) may be used, such as image of a fingerprint or a biometric template (e.g. LBP) derived therefrom. For this to be effective, a high resolution image of the fingerprint is needed. Where the device's camera is not equipped to provide an image with the necessary resolution, super resolution imaging can be used, whereby multiple images of the fingerprint are captured and combined using known super- resolution techniques to generate a composite fingerprint image having a greater image resolution than any of the individual images. The composite image is preferably generated at the user device, though is can be implemented by the uPass system. Accordingly, any of the above description pertaining to a selfie applies equally to a fingerprint image data (or other biometric data).

Liveness detection in Enrolment

In some embodiments, during the enrolment process in which the image of the passport is captured, that same image (or images) may be used for liveness detection. That is, the uPass system may, upon receiving an image of an identity document, process it to simultaneously verify that the document is authentic and also that the hand holding it is a real, human hand (e.g. based on texture analysis). That is, document authentication and liveness detection may be performed based on the same image(s). The authenticity of the document and the liveness of the hand holding it may be prerequisites for anchoring the document within the system.

Glossary

Term Description May associate Example with

Account creation A message used in the

message account creation process

Acquired Credential A candidate Credential

acquired via mechanisms

known to a specific Client

Application.

An uPass At least one (uPass) profile

with at least one credential

bound to it

Anchor confidence or issuing

Authenticator A service authorised to

broker a Transaction

between two Registered

Devices.

Blob a binary data element

Client Application A software application

running on a Registered

Device and capable of

storing a Current

Credential.

Confidence Confidence Network,

Framework? Confidence Web Confidence anchor a uPass profile which is Another uPass used to assert the validity of user a upass profile belonging to

a different uPass user

Confidence value the numeric value assigned

to an uPass profile based on

the sum of the confidence

and issuing anchors

Contingent Trust A value indicating the

trustworthyness of a

particular profile or data

titem based upon its

confidence value and the

usage of this profile or data

item over time

Credential A token binding a specific a proflie, a

Profile to a Registered registered device, a

Device, both associated receipt

with an Identity. This token

is unique and may only be

used once. Optionally it

may also be time-limited or

invalidated.

Current Credential The Credential which is

valid for a specific Profile

and Registered Device at a

given point in time.

Data element a combination of a data

item and associated

metadata

Data Item Data Element

HMAC In cryptography, a keyed- hash message

authentication code (HMAC) is a specific construction for calculating a message authentication code (MAC) involving a cryptographic hash function in combination with a secret cryptographic key. As with any MAC, it may be used to simultaneously verify both the data integrity and the authentication of a message

HSTS HTTP Strict Transport

Security (HSTS) is a web security policy mechanism which is necessary to protect secure HTTPS websites against downgrade attacks, and which greatly simplifies protection against cookie hijacking.

Identifying Anchor identifying document

Identity Assertion Any atomic key value pair representing a statement about the identity of the uPass User

Identifying document issuing document

Identity The characteristic

information associated with a single user. An identity many consist of many profiles Identity statement profile

Issuing anchor the author of an issuing like the crown document for a passport

Issuing document a source document from profile Passport,

which a profile may be Driving Licence, created Utility Bill, ID card, Student card

Master Receipt Book A central repository of

Receipts of all uPass Users.

Merchant registered corporate entity,

sole trader, partnership,

registered charity, club,

society etc.

Profile A cohesive set of one or

more Identity Assertions

describing some aspect of

an identity, combined with

a photo and linked to the

contingent trust system

Profile History A time sequence of stored

versions of a Profile for a

given Identity along with

associated metadata.

Published Profile An instance of a Profile at a

given point in time, stored

encrypted in a randomly

selected and publicly- accessible location.

Receipt A token created subsequent

to a Validation which

contains key metadata

related to that Transaction

and links to a Published

Profile for the other party involved in that

Transaction.

Receipt Book A time sequence of Receipts associated with a specific Identity

Receipt Pair Receipts are generated in pairs so that each party to a Transaction receives one. The Receipt Pair are bound together by a shared Transaction ID which is used as a shared symmetric key to encrypt both associated Published Profiles.

Registered Device Any computing system

registered as valid for a given identity

Registration data Sum of all data items

submitted for registration

Registration documents submitted issuing

documents

Registration item registration Datum

Registration Event The act of submitting or resubmitting an identity Document to the Secure Store, allowing its baseline Contingent Trust to be determined Remote Connect The mechanism whereby an intermediary unassociated with the system is used to present a Credential from a Virtual Device hosted in a remote service such as a web server. This Credential is then acquired by a registered Device which acts as a Validator.

Security Event a message sent to a

separate security auditing and enforcement system

Seifie A self-taken photo of a user, in particular of their face

Social graph mapping and pinpointing a uPass user in relation to other uPass users

System Application One or more software

applications which together use a series of Transactions to perform a more complex task.

Transaction ID A cryptographically random, unique number used to identify a given Transaction.

Transaction Key transaction ID

Trust Arbitration An automated mechanism which establishes trust in a timely manner between two users via proffered credentials uPass User An entity registered to the Some of the uPass system that has been document type assigned at least one profile and the method of submission is contingent trust

Validation Transaction The process of confirming

that an acquired Credential

is valid and current for a

given Registered Device,

leading to the creation and

dissemination of a Receipt

Pair.

Validator A Registered Device capable

of acquiring a Credential

from another registered

Device and using this to

request a Validation via an

Authenticator.

Virtual Device A notional Registered

Device which exists purely

as an embodiment in

software hosted on a

physical Registered Device.

Aspects of the subject matter and embodiments thereof Various aspects of the present subject matter, and embodiments thereof, are set out below.

An aspect is directed to a method of authenticating content offered by a content source to a local device for displaying content, the method comprising: establishing a communication session between the content source and a browser executing at the local device; transmitting from the content source to the browser a validation page comprising a content authentication token which is a randomly generated one-time use only credential bound to the content source; capturing the content authentication token from the browser by a verification application; transmitting the authentication token to a validation service which determines whether the token is bound to a valid source of content; and causing the content to be displayed on the local device if the token is bound to a valid source of content In embodiments, causing content to be displayed may comprise transmitting a content source receipt from the validation service to a mobile device with or indicating a data item relating to the valid source of content. The content source receipt may comprise a link identifying a memory location from which the data item is accessible, thereby indicating the data item. The data item may be accessed from a digital profile of the content source identified by the credential. The profile may be published by storing a version of it to an addressable memory location, and a link identifying the addressable memory location is included in the content source receipt, thereby indicating the data item. The verification application may be executed on the mobile device which captures the content authentication token displayed on the validation page by one of: digital image capture; scanning, near field communications and Bluetooth.

The content authentication token may be received by a local browser of the local device and transferred to the verification application which is executed in the local device.

Causing the content to be displayed may comprise transmitting a receipt to the local device which indicates a data item relating the valid source of content.

The token may identify an address of the source of content, the method may comprise transmitting the address to an address verification service to confirm the address is a valid address. The data item may be displayed at the mobile device. The data item may be details of a server hosting the content. The data item may comprise details of a virtual device hosting the content and/or a physical device on which the virtual device is running. The method may comprise the steps of transmitting from the mobile device a device authentication token which is a randomly generated one-time use only credential bound to the mobile device to the verification service with the content authentication token. The validation service may use the device authentication token to access a digital identity profile using the credential. The validation service may generate a device identification receipt comprising or indicating a data item accessed from the digital identity profile and transmits the receipt to the content source. The content source may determine whether or not to release content based on the data item in the device identification receipt. The method may comprise transmitting in the device identification receipt a fresh device authentication token.

The method may comprise a fresh content authentication token to the content source.

The device identification receipt and the content source receipt may share a common transaction identifier.

The method may comprise the steps of transmitting from the local device an authentication token which is a randomly generated one-time use only credential bound to the local device to the verification service with the content authentication token.

The source of content may comprise a server, and the token may be bound to the server. The content source may comprise a server, and the content authentication token may be bound to a transient virtual device created by the server in a session establishment procedure instigated by the local device.

A confidence value may be associated with the data item and displayed with the data item.

Another aspect is directed to a computer system comprising:

a digital identity system configured to implement a validation service;

a local device comprising a network interface and a processor configured to execute a browser which operates to:

establish a communication session between a content source and the browser via the network interface, and

receive from the content source a validation page comprising a content authentication token which is a randomly generated one-time use only credential bound to the content source;

wherein a verification application captures the content authentication token from the browser and transmits the authentication token to a validation service which determines whether the token is bound to a valid source of content; and

wherein the validation service causes the content to be displayed on the local device if the token is bound to a valid source of content.

In embodiments, the verification application may be executed on the local computing device. The computer system may comprise a mobile device, which comprises a processor and a network interface, wherein the verification application is executed on the processor of the mobile device.

Another aspect is directed to a digital identity system for creating a computer stored digital identity comprising:

a network interface configured to send and receive electronic messages; persistent electronic storage; a profile management module configured to receive from an entity an electronic message comprising a data item, extract the data item from the electronic message and store the data item in a digital profile in the persistent electronic storage;

a credential creation module configured to generate a credential for the profile and associate the credential with the digital profile;

a receipt generation module configured to automatically generate two non- matching receipts, each receipt comprising a transaction identifier, a first of the receipts comprising a link identifying the memory location to which the profile is published, a second of the receipts comprising the credential, wherein the first receipt is stored at the digital identity system and the second receipt is transmitted to an address associated with the entity; and

a publication module configured to publish the profile by storing a version of it to an addressable memory location;

In embodiments, a master receipt comprising data of each receipt may also generated and stored in a master receipt book at the digital identity system, whereby both the first and the master receipt are stored at the digital identity system. The master receipt may comprise only part of the first receipt. The master receipt may comprise the link but not the credential. For instance, the master receipt may comprise the link and the transaction identifier, but not the credential. Alternatively, the data of each receipt in the master receipt may be encrypted with the transaction identifier, wherein the master receipt does not include the transaction identifier. The credential may be a randomised one-time only use credential.

Multiple digital profiles associated with the entity may be created each profile being associated with a credential unique to that profile, wherein each digital profile may be published by assigning a unique set of data items for each digital profile to a corresponding addressable memory location. The data item may be shared between the unique sets. For instance, one of the sets may consist only of the data item, and the remaining sets may each comprise the data item and at least one additional data item. The data item may be a visual image of the entity.

The multiple data items may be received in the electronic message and stored in the profile. Metadata available from a computer device associated with the entity may be received with the data item and stored at the digital identify system. The credential may be generated using the metadata. For instance, the credential may be generated by a hash of the metadata and a random salt. The random salt may be stored in association with the metadata, whereby a copy of the credential can be generated from the stored random salt and stored metadata. The credential may be generated by hashing the device metadata and the random salt a random number of times, wherein the random number may be stored in association with the random salt and the metadata. The metadata may comprise an identifier of the computer device (device identifier).

The credential may be associated with the digital profile by creating an entry in a database, the entry comprising the digital profile or an indicator which enables the digital profile to be located in the persistent electronic storage, wherein the

publication module may be configured to use the credential as a key to that entry in the database to access the profile for publication.

The profile may be published in response to the credential being presented to the digital identity system. The credential is presented by a validating entity other than the entity, the credential having been provided to the validating entity by the entity. The credential may be one-time only use, and the credential creation module may be configured to generate a fresh credential in response to the credential being presented to the digital identity system, whereby another version of the profile is published to a different addressable memory location by the publication module in response to the fresh credential being presented to the digital identity system.

A device identifier may be received with the data item and stored at the digital identify system, wherein publication of the profile may be conditional on a matching device identifier being presented with the credential.

The link may be generated from and/or the memory location may be selected based on a randomly generated sequence.

The link may be is a Uniform Resource Indicator (URI).

The digital identity system may comprise a confidence value management module configured to allocate a confidence value to the profile based on at least one of a source of the electronic message and a type of the data item. The confidence value may be published with the profile, whereby the confidence value and the profile are available to a requesting entity.

The confidence value may be changed over time based on a clock signal.

Another aspect is directed to a computer-implemented method for creating a computer stored digital identity comprising:

receiving from an entity an electronic message comprising a data item;

extracting the data item from the electronic message;

storing the data item in a digital profile in the persistent electronic storage; generating a credential for the profile and associating the credential with the digital profile; automatically generating two non-matching receipts, each receipt comprising a transaction identifier, a first of the receipts comprising a link identifying the memory location to which the profile is published, a second of the receipts comprising the credential;

storing the first receipt at the digital identity system; and

transmitting the second receipt an address associated with the entity; and publishing the profile by storing a version of it to an addressable memory location. Another aspect is directed to a method of registering a digital identity comprising: capturing at a computer device a data item associated with an entity;

creating an electronic message comprising the data item;

transmitting the electronic message to a registration service;

receiving a receipt from the registration service;

extracting a credential from the receipt to render the credential available for accessing the data item for authenticating the entity; and

storing the receipt in a local receipt book at a location accessible to the computer device. In embodiments, the data item may be captured in the form of an identifying datum from an identity document.

The data item may be captured the form of a photo taken by a camera of the computer device.

The first data item may be captured by one of: scanning, near field access; and Bluetooth.

The local receipt book may be held at a server accessible to the device. Another aspect is directed to a method implemented by executing digital identity software on a processor of a user device to:

capture with a camera of the user device an image of the face of a user of the device;

capture data from a real-world identity document, the data including an identification photograph, wherein the data is captured with the camera, from an electronic transmitter embedded in the anchoring document, or a combination of both;

transmit the image of the user and the captured data to a digital identify system; and

receive from the digital identify system a credential for the user, wherein presentation of the credential to the digital identity system renders at least part of the captured data available to a presenting entity. In embodiments, the captured data may also comprise an attribute of the document,

The identity document may be a passport or driving licence.

The user device is may be smart device, such as a smartphone or tablet.

Another aspect is directed to a user device comprising:

a camera;

a processor configured to execute digital identity software which operates to: capture with the camera of the user device an image of the face of a user of the device;

transmit the image of the user and the captured data to a digital identify system; and receive from the digital identify system a credential for the user, wherein presentation of the credential to the digital identity system renders at least part of the captured data available to a presenting entity. Another aspect is directed to a computer implemented method implemented by a digital identity system, the method comprising:

receiving in an electronic message from a user device: an image of the face of a user of the user device which has been captured at the user device; and data which has been captured from a real-world identity document and which comprises an identification photograph;

storing at least part of the captured data at the digital identity system in persistent electronic storage;

comparing the image of the face with the identity photograph using a facial verification algorithm; and

only if the image of the face matches the identification photograph, generating a credential for the user and transmitting the credential to the user, wherein presentation of the credential to the digital identity system renders at least part of the stored data available to a presenting entity. In embodiments, an attribute of the document may be received in the message, and the credential may be generated and transmitted only if the attribute meets a predetermined criteria. The photograph and/or image may be made available to the presenting entity. Another aspect is directed to a digital identity system comprising:

a network interface configured to send and receive electronic messages; a processor configured to perform operations comprising:

receiving in an electronic message from a user device: an image of the face of a user of the user device which has been captured at the user device; and data which has been captured from a real-world identity document and which comprises an identification photograph; storing at least part of the captured data at the digital identity system in persistent electronic storage;

comparing the image of the face with the identity photograph using a facial verification algorithm;

only if the image of the face matches the identification photograph, generating a credential for the user; and

transmitting the credential to the user, wherein presentation of the credential to the digital identity system renders at least part of the stored data available to a presenting entity.

Another aspect is directed to a method of authenticating a digital credential of a bearer by a validating device, the method comprising:

capturing the bearer credential by the validating device;

transmitting to a validation service the bearer credential with a validator credential bound to the validating device;

at the validation service, validating the bearer credential and the validation credential, and if the validator credential is valid, using the bearer credential to access a data item of a digital profile and creating an electronic message for transmission to the validating device, the electronic message indicating the data item and comprising a fresh validator credential generated by the validation service;

issuing a fresh bearer credential and creating an electronic message to transmit the fresh bearer credential to an address associated with the bearer.

In embodiments, the method may comprise the step of using the validator credential to access a data item of a digital profile associated with the validating device and creating an electronic message for transmission to the bearer, the electronic message indicating a data item for verification by the bearer.

The electronic message may indicate the data item by providing a link to a version of the digital profile held at an addressable memory location identified in the link. The electronic message which indicates the data item for verification by the bearer may indicate the data item by providing a link to a version of the digital profile associated with the validator at an addressable memory location indicated by the link. The data item may comprise a visual image of the bearer or validator respectively.

The fresh bearer credential may be generated for transmission to the bearer is comprised in a receipt having a transaction identifier. The validation service may generate a master receipt, wherein the master receipt may be stored in a master receipt book. The validation service may generate a master receipt having the same transaction identifier as the receipt generated for transmission to the bearer, wherein the master receipt may be stored in a master receipt book. Alternatively, part of the master receipt may be encrypted with the transaction identifier, in which case the transaction identifier is not included in the master receipt.

The fresh validator credential may be comprised in a non-matching receipt having the same transition identifier.

The address associated with the bearer may comprise an address of a device previously registered by the bearer and stored in association with the bearer credential.

The step of generating a fresh credential may comprise using a randomly generated sequence to generate a fresh credential bound to the digital profile.

The credentials may be one-time only use.

Another aspect is directed to a method of providing access to digital profiles held in persistent electronic storage of a digital identity system, the method comprising: receiving from a requesting entity an electronic request message identifying a target entity; in response to the request, publishing: (i) a digital profile of the target entity by storing a version of that profile in an addressable memory location, and (ii) a digital profile of the requesting entity by storing a version of that profile in another addressable memory location;

generating two non-matching receipts, each comprising a transaction identifier, a first of which comprises a link identifying the memory location to which the target entity's profile is published, the second of which comprises a link identifying the other memory location to which the requesting entity's profile is published;

transmitting the first receipt to an address associated with the requesting entity; and

transmitting the second receipt to an address associated with the target entity.

In embodiments, a target credential may be associated with the target entity's profile and a requestor credential may be associated with the requesting entity's profile in a database of the digital identity system, and the step of publishing may be conditional on matching target and requestor credentials being received in the electronic request message. The credentials may be one-time use only, and the method may comprise generating a fresh target and a fresh requestor credential and associating them with the target entity's profile and the requesting entity's profile in the database respectively, the fresh target and requestor credentials being included in the second and first receipt respectively.

The method may comprise storing a master receipt at the digital identity system, the master receipt comprising data of both receipts and being stored in a master receipt book. The master receipts may comprise both links but may not include the fresh credentials. The data of both receipts in the master receipt (e.g. the links) may be encrypted with the transaction identifier, in which case the transaction identifier is not included in the master receipt.

The master receipt may comprise both links and the transaction identifier but may not include the fresh credentials.

The target entity may be a bearer and the requesting entity a validator, the bearer's profile being a pre-existing digital profile which is accessed in the persistent electronic storage in response to the request.

The target entity may be a registrant and the requesting entity may be an enrolment module of the digital identity system which has created the digital profile in the persistent electronic storage. A respective confidence value may be allocated to each profile which is published with that profile and accessible via the respective link.

Another aspect is directed to a computer system comprising a network interface configured to transmit and receive electronic messages, and a processor configured to implement the method of any preceding claim.

Another aspect is directed to a digital identity system comprising:

a network interface configured to send and receive electronic messages;

persistent electronic storage holding a digital profile of a target entity and a digital profile of the requesting entity;

a publication module configured to receive from the requesting entity an electronic request message identifying the target entity and, in response to the request, publish: (i) the target entity's digital profile by storing a version of that profile in an addressable memory location, and (ii) the requesting entity's digital profile by storing a version of that profile in another addressable memory location; a receipt generation module configured to generate two non-matching receipts, each comprising a transaction identifier, a first of which comprises a link identifying the memory location to which the target entity's profile is published, the second of which comprises a link identifying the other memory location to which the requesting entity's profile is published, wherein the first receipt is transmitted to an address associated with the requesting entity and the second receipt is transmitted to an address associated with the target entity.

Another aspect is directed to a digital identity system comprising:

an enrolment module configured to receive a data item from an enrolling device and to create in persistent electronic storage a digital profile comprising the data item;

a credential creation module configured to generate a credential from a random sequence, to associate the credential with the digital profile in a database, and to transmit the credential to the enrolling device;

a publication module configured, in response to later presentation of the credential to the digital identity system, to publish the digital profile by storing a version of the digital profile in a memory location accessible to a device presenting the credential.

In embodiments, the enrolment module may be configured to also receive metadata of the enrolling device, which is stored in the database in association with the profile.

The credential may be generated from the random sequence and the metadata, and the credential may be associated with the profile by storing the random sequence and the metadata in the database in association with the profile, and wherein the system may comprise a validation module configured to generate a copy of the credential from the sequence and metadata stored in the database, and the publication of the profile may be conditional on the presented credential matching the copy. The metadata may comprise an identifier of the enrolling device, and the publication of the profile may also also conditional on a matching device identifier being presented with the credential, whereby use of the credential is restricted to the enrolling device.

The credential may be associated with the profile by storing a copy of the credential in the database in association with the profile, wherein the system may comprise a validation module configured to validate the presented credential by comparing it with the copy and the publication of the profile may be conditional in the presented credential being valid.

A link identifying the addressable memory location may be transmitted to the presenting device. The link may be generated from a random sequence. The addressable memory location may be selected based on a random sequence.

Another aspect is directed to a digital identity system according to claim 1 wherein the persistent electronic storage also holds another digital profile associated with another credential and comprising a data item which has been received from the presenting device, wherein both credentials are presented by the presenting device, and in response the other profile is published to a different memory location accessible to the enrolling device. In embodiments, the digital identity system may comprise a receipt generation module configured to generated two non-matching receipts, one of which is transmitted to the presenting device and comprises a link identifying the memory location to which the profile is published, the other of which is transmitted to the enrolling device and comprises a link identifying the other memory location to which the other profile is published. The digital identity system according may comprise a confidence value allocation module configured to allocate a confidence value to the profile based on at least one of: a type of the received data item and a source of the data item. Another aspect is directed to a method implemented at a digital identity system and comprising:

receiving a data item from an enrolling device;

creating in persistent electronic storage a digital profile comprising the data item;

generating a credential from a random sequence;

associating the credential with the digital profile in a database;

transmitting the credential to the enrolling device, wherein later presentation of the credential to the digital identity system causes publication of the digital profile by storing a version of the digital profile in a memory location accessible to a device presenting the credential.

Another aspect is directed to a method of providing access to a digital profile comprising:

receiving a one-time only use credential associated with a digital profile in persistent electronic storage;

validating the credential and, only if the credential is valid, publishing the profile to an addressable memory location by storing a version of it at the memory location, thereby invalidating the credential;

generating a fresh one-time only use credential for the digital profile;

associating the fresh credential with the digital profile; and

transmitting the fresh credential to an address associated with an entity, whereby the entity can use the fresh credential once thereafter to cause the profile to be republished to a different addressable memory location. Another aspect is directed to a computer system comprising a network interface and a processor configured to implement the method. Another aspect is directed to a computer system comprising:

electronic storage;

a network interface configured to receive electronic messages ;

a processor configured to execute identity management code which operates to:

receive an electronic message from the network interface, the message including at least one data item to be included in a digital profile for an entity, the data item associated with the entity and uniquely identifying the entity; extract the data item from the electronic message;

create and transmit a credential to the entity, wherein presentation of the credential to the computer system renders a version of the digital profile and the confidence value available to a presenting entity. In embodiments, the electronic may hold a plurality of digital profiles associated with the entity, each digital profile comprising a unique set of data items for that digital profile. At least some of the data items may be shared between the unique sets.

In embodiments, the electronic storage may hold anchoring documents in association with the digital profiles, wherein an anchoring document may be received in the electronic message and the data item has been extracted from the anchoring document.

The confidence value may be allocated based on the type and/or age of the anchoring document. The confidence value may be allocated based on the source of the anchoring document.

The version of the profile may be rendered available by storing it to an addressable memory location, and transmitting a link identifying the memory location to the presenting entity.

The processor may be configured to create and transmit a credential each time a data item is stored in a digital profile, wherein presentation of each credential to the computer system may cause a respective version of it to be stored to a different addressable memory location, whereby multiple versions of the profile may be published.

The memory location may be selected based on a random sequence. The link mat be generated from a random sequence.

The link may be a Uniform Resource Indicator.

One of the data items may be a visual image of the entity.

The entity may be a person and the visual image is a facial image of the person.

The electronic storage may comprise a device metadata storage section which holds metadata associated with computer devices which have been used to transmit electronic messages to the network interface.

The electronic storage may hold one or more digital profiles for each of multiple entities. The digital profile may comprise multiple data items received from the entity. The identity management code may be operable to allocate a confidence value associated with a source of the electronic message, such that when the source of the electronic message is unknown to the computer system, the confidence value is low. When the source of the electronic message is known to the computer system, the identity management code may be operable to allocate a confidence value appropriate to the status of the source of the electronic message.

When the source of the electronic message is a document issuing authority, the confidence value which is allocated may be high.

The identity management code may be operable to allocate a confidence value such that when one of the multiple entities which has a digital profile held in the electronic storage is the source of the electronic message, a contingent trust value associated with that entity is used to calculate the confidence value.

The contingent trust value may be dependent on usage of the digital profile by the multiple entities in one or more authentication process. The identity management code may be operable to update the digital profile on receipt of further data items, and wherein the allocated confidence value is changed when the profile is updated.

The processor may be configured to change the allocated confidence value over time based on a clock signal.

The confidence value may be increased in response to receiving an additional visual image of the entity. The entity may be required to present a new data item when subsequently logging on to the system, and the confidence value may be changed based on the new data item. The new data item may be a visual image of the entity.

The identity management code may be operable to receive a data item from a third party to assign a profile to the entity, and wherein the confidence value which is allocated may depend on the status of the third party.

The electronic message may be received from the entity.

The electronic message may be received from another entity different than the entity. The data item may be one of two data items are received in the message, a first of which is an image of the entity which has been captured with a camera and the second of which is an identification photograph which has been captured from a real- world identity document, and the confidence value may be allocated by comparing the two data items and may reflect an extent to which they match, The two data items may be compared using a facial verification algorithm.

Another aspect is directed to a computer-implemented method of managing a digital profile comprising: receive an electronic message including at least one data item to be included in a digital profile for an entity, the data item associated with the entity an uniquely identifying the entity;

extracting the data item from the electronic message;

creating a digital profile using the data item in electronic storage, wherein the profile comprises the data item;

allocating a confidence value to the profile, wherein the confidence value is allocated based on at least one of a source of the electronic message and a type of the data item; and creating and transmitting a credential to the entity, wherein presentation of the credential to the computer system renders a version of the digital profile and the confidence value available to a presenting entity. Another aspect of the present invention is directed to a digital identity system comprising a data store having at least one storage location, at which identity data of an entity is held; a computer interface configured to receive an electronic message, which identifies the storage location of the entity's identity data in the data store, wherein the message comprises a one-time use only credential of the entity; and a computer system configured to validate the credential and, if the credential is valid, retrieve the entity's identity data from the identified storage location, issue a fresh one-time use only credential to the entity, and publish the retrieved identity data by storing a version of it to an addressable memory location; wherein the computer system is configured to generate in a master receipt store a master receipt, wherein the master receipt comprises a link to the addressable memory location and an index which comprises a hash of the fresh credential.

In embodiments, the master receipt may also comprise a hash of the credential received in the electronic message.

The computer system may be configured to provide to another entity, in response to receiving a grant of access by the entity to the other second entity, a receipt comprising a copy of the link whereby the other entity can access the entity's published identity data.

The receipt may comprise a transaction identifier, wherein the link in the master receipt and/or the published identity data at the addressable memory location is encrypted with the transaction identifier. The computer system may be configured to provide the receipt to the other entity only if it has received a valid one-time only use credential of the other entity in association with the grant of access, wherein in that event a fresh one-time only use credential is issued to the other entity by the computer system, wherein the master receipt comprises another index comprising a hash of the fresh credential issued to the other entity.

The computer system may be configured to provide to the entity another receipt which comprises the same transaction identifier.

The grant of access may be denoted by the electronic message comprising the credential of the entity.

The electronic message comprising the credential of the entity may be received from the entity. The electronic message comprising the credential of the entity may be received from the other entity.

In response to receiving a copy of the credential at a later time in an electronic search request message via the computer interface, the computer system may be configured generate a search index comprising a hash of the credential received in the search request message, use the search index to locate the master receipt in the master receipt.

The computer system may be configured generate a search index comprising a hash of the credential received in the electronic message, use the search index to locate in the master receipt store an earlier master receipt having an index that matches the search index, and generate a hash and/or a digital signature from at least part of the earlier master receipt, wherein the master receipt also comprises the hash of the at least part of the earlier master receipt. The hash and/or the digital signature may be generated from substantially all of the earlier master receipt, including its index.

The other entity may hold a symmetric or private key, and the computer system may be configured to encrypt the other receipt using a version of the private key or a corresponding public key available at the digital identity system.

The entity may hold a symmetric or private key, and the computer system may be configured to encrypt the other receipt using a version of the private key or a corresponding public key available at the digital identity system.

The hash of the credential in the master receipt may be encrypted with the transaction identifier. The grant of access may be denoted by a later electronic message received via the computer interface after the electronic message comprising the credential of the entity.

The electronic message may be a sharing token request received from the entity, wherein the computer system is configured, if the credential is valid, to issue to the entity in response a sharing token bound to the identity data in the identified storage location, wherein the other electronic message may be received from the other entity and comprise the sharing token. Another aspect is directed to a method comprising implementing any of the above described system, device, application or other functionality.

Another aspect is directed to a computer program product comprising code stored on a computer readable storage medium and configured to implement any method, system or device functionality disclosed herein. The system and method described above may, in embodiments, be used for any of the following. Note that the "uPass system" is sometimes referred to herein as a "YOTI system". The terms "uPass" and "YOTITYoti" used interchangeable in this disclosure. uPass Connect

The uPass Connect mechanism can be used for the following purposes:

• Verifying identity (ID) Online

• Verifying age online

• KYC (Know Your Customer) mechanisms

• No-phishing i.e. as an anti-phishing mechanism

• Multi Factor Authentication

• Bots Prevention

• Preventing Multiple Accounts (i.e. being opened by the same entity)

• To implement "One user one Vote" voting mechanisms, e.g. for:

o Competition Entries

o Voting

o Polling

o Lobbying

o Petitions

• anonymous but verified login

• to create a profile blacklist e.g. to provide Anti Touting

• authentication without usernames + passwords

• form filling / registration

• restricting access to content by:

o Location

o Age

o Nationality

o Name o DOB

o Address

o other 'profile' details

• Send a user's identity over the Internet

The following are additional, useful configurations and/or uses of the uPass system: F2F (Friend to Friend/Peer to Peer)

The uPass system can be configured in an F2F context. For example is can be configured to provide mechanisms for the following:

• Entry to a building via QR code / NFC

• entry to venues by proving profile + permissions. Profile details which may be provided include:

o Company

o Age

o Nationality

o Name

o DOB

o Address

o Do you have the correct ticket

o Do you have the correct security clearance

o other profile details

• Proving age for access control / point of sale, for example at:

o Nightclubs

o Casinos

o Pubs

• Signing into a location, for example in the following contexts:

o Roll Call e.g. schools

o Visitor Book o Courses

o Health and Safety

o Hotels / BnBs

o Gyms

• Logging hours worked

• Hotel use case - book via connect, assign pass to device, avoid check-in + key cards

• Proving ID to another individual, for example in the context of:

o Classifieds

o Dating

o Taxis

o Flatshare

o Carshare

• Business proving ID to an individual - e.g:

o for use during home visits:

o for showing to employer

o for showing appropriate qualifications

• Individual proving ID to business, for example:

o Pawnbrokers

o Car Rental

o High Value Purchases

o Age Restricted Goods

o Goods collection

o Transport

• Home Delivery, for example to provide:

o Proof of Receipt of Goods

o Authorisation to individuals to collect goods on your behalf

• F2F and online KYC, e.g. in the context of: o Estate / Lettings Agents

o Creating bank accounts

o Insurance

o Mortgage

o Peer2Peer lending

• Employee proving ID to business, for example demonstrating:

o Right to work inc.:

^■ Visas

^■ Qualifications

^■ Nationality etc

o User Access to Business Applications

o Building Access

o Certifications e.g.:

^■ Health and Safety Course

^■ Forklift Driver

^■ First Aid

^■ Child Protection

^■ CRB

^■ License to Practice

o Insurance, e.g.:

^■ Indemnity Insurance

^■ Liability insurance

Yotis issued by third parties

Examples of third parties that can usefully issue Yoti's are:

• Parents

• Businesses

• Charities, e.g.: o Diaster relief - charity can issue a temporary identity until such a time when the country's infrastructure has improved

o Using Yoti to assign a unique identifier e.g. QR code or an NFC chip to an identity. Yoti is capable of working in an offline capacity

Asset Tags

• Assigning an identity to an object

• Digital watermarks

o Assigning an identity to digital content

o Assigning an identity to tickets

• Tagging pets

• Assigning an identity to

o Certificates

o Documents

IOT (Internet of Things)

• Assigning permissions to loT connected devices based on a Yoti identity

• Allowing devices to communicate with individuals

MOOCS

• Online tests, e.g.

o Random face checks to verify identity

o Verify identity of examinee

o Assigning qualifications

Global address book

• Sharing a user's contact information with others which gets updated when the user updates • Being able to restrict access to your contact information

• Sharing business cards

Restricting Online Content

* Paywall infront of content

• Micropayments

• Subscription Services

Microdonations

Messaging system for healthcare patients to give and receive feedback

Loyalty scheme management

• registering to loyalty schemes

· proof of membership, loyalty level, points allocation

Club management

• registration to clubs / societies

• proof of membership, proof of subscription payment, proof of membership level

• membership communication

• payment of subscritpions and other items relating to club

Digital signatures

· signing electronic format contracts (like DocuSign)

• acknowledging agreement to an agreement created and hosted on Yoti

Escrow Services

• domain name transfers

· other electronic item transfers • physical good transfers (e.g. City exchanges)

Invoices

• A service to issue invoices. This would be a useful product for some premium Yoti Individuals / smaller service providers (cleaning lady, electrician, plumber, etc.).

• Disruption to the insurance by using Yoti connect and verifying ID it is possible to can mitigate false insurance; this in turn creates a lower premium due to lower risk due to a verified identity

AML (Anti Money Laundering)

• Credential Management Apps - Across Devices

• Private Messaging System - Like Wickr but with a guaranteed identity

• Encrypt emails using Yoti, e.g. to provide:

o Digital signatures and encryption using Yoti idenitties for permission

DIGITAL VAULT

• Personal vault linked to identity, e.g. for:

o Documents

o Qualifications

o Digital Content

o Medical records

o Wills

o Share Certificates

· Cryptographic key store - allow yoti to store keys to unencrypt secure

documents stored elsewhere

TICKETING

• Verifying Identity

· Prevent Bots • Prevent Multiple Accounts

• Control Purchasing of Tickets

• Blacklists

• Tout Profiles

· Assign Identity To Tickets

• Purchase of Tickets (through e-wallet)

• Controlled Resale of tickets

• Event Entry Control

• Ballots

· Offer events a profit share on the resale of tickets EWALLET

• Building an e-wallet ontop of an identity system

• Social Savings

· Pocket Money / Childrens ewallet

• P2P Payday lending

• Charity Donations

• Associating profiles with contactless payments

• Cryptocurrencies

· Tying in identity with cryptocurrencies

• Secure Ledger , e.g. for managing:

o Cyrpotcurrency - removes need for distributed ledgers

• Microdonations

• Transferring funds

SECTORS

The following uses within the following sectors are envisaged: Freelancers • Verifying Previous work e.g. associate identity to previous designs

• Reviews

• Prevent multiple accounts

• Payments (through eWallet)

• Verifying qualifications

Sharing Economy

o B2B (Business to Business)

■ Verifying Users

■ Verifying ownership of shared goods

^■ Registration / Login

^■ Payments (through ewallet)

(Business to Consumer)

Allow users to send identity to each other over the internet Allow users to show identity in person

Classifieds

o B2B

^■ Verifying Users

^■ Verifying ownership of shared goods

^■ Registration / Login

Allow users to send identity to eachother over the internet Allow users to show identity in person

Payments (through ewallet)

Online Dating

o B2B ^■ Verifying Users

^■ Prevent Bots

^■ Prevent Multiple Accounts

^■ Registration / Login o B2C

^■ Allow users to send identity to eachother over the internet

■ Allow users to show identity in person

^■ Temporary Chat

Online Gaming

• AML

• KYC

• Prevent Bots

· Prevent Multiple Accounts

• Secure Login

• Payments (through ewallet)

DRM Content Management

· Assign Identities to Digital Goods

• Allow resale of digital goods through Yoti

Age Restricted Content

• Anonymous Age Verification

· Secure Login

• Prevent Sharing of Login Details

• Age Restricted Chat Rooms

• Childrens Games Ticketing / Events / Conferences • Verifying Identity

• Prevent Bots

• PRevent Multiple Accounts

• Control Purchasing of Tickets

• Blacklists

• Tout Profiles

• Assign Identity To Tickets

• Purchase of Tickets (through e-wallet)

• Controlled Resale of tickets

• Event Entry Control

• Ballots

Third Sector

• Disaster relief - charity can issue a temporary identity until such a time when the country's infrastructure has improved

• Using Yoti to assign a unique identifier e.g. QR code or an NFC chip to an identity.

MOOCs / Training

• Verify Identity of Candidates

• Assigning Qualifications

• Checking Identity of Examinees

• Face Matching during online Exams

• Secure Login

Review Sites

• Prevent Bots

• Prevent Duplicate Accounts

• Prevent Fake Reviews

• Secure Login • Verifying Businesses

Public Health

• Verifying Employees

· Verifying Visitors

• Storage of I Patients Health Records

• Asset management

• Building Entry

• Doctor Patient Messaging

· Patient Feedback

• Online Appointment Booking

Delivery Services

· Verifying Identity of Individuals Picking up parcels

• Giving friends/family permission to pick up parcels on your behalf

• Signing for Parcels- Receipt of Delivery

• Verifying employees

• Asset Management, e.g.:

o Employees signing out vans/cars

Recruitment

• Verifying Identities of candidates, e.g:

o Qualifications

o Visas

o Nationalities

• Sharing identity with HR

• Sharing contact details Retail • Discounts Based on profile items

• Loyalty Schemes

• Proof of membership

• Proof of age

• Competitions

• Data Capture of shoppers

• EPOS

• Building Access

• Online Retail Login

• Online Retail Registration

• Payments (through eWallet)

Company Profiles

• Business proof of identity to customer on home visits

• Proof of qualifications to customer

• Proof of receipt of visit

• Proof of work done

Residential

• KYC

• Proof of right to live

• Contact sharing

Financial Services

• KYC

• AML

• Secure online login

• Disruption to the insurance by using Yoti connect and verifying ID we can mitigate false insurance, creates a lower premium due to lower risk due to a verified identity • Building Access

Universities

• Building Access

· Secure online login

• Receipt of work Submissions

• Verifying identity of students

• Verifying Visas

• Payments (through ewallet)

· Library book loans

• Club / Society Memberships

• Age Verification at Bars

• Roll call for lectures/seminars Travel

• Storing Tickets

• Proof of age for discounts

Public Sector

· Voting and Polling - Online and Offline

Asset Management.

uPass Connect

The uPass Connect mechanism can be used for the following purposes:

· Verifying identity (ID) Online

• Verifying age online

• KYC (Know Your Customer) mechanisms

• No-phishing i.e. as an anti-phishing mechanism

• Multi Factor Authentication

· Bots Prevention

• Preventing Multiple Accounts (i.e. being opened by the same entity) To implement "One user one Vote" voting mechanisms, e.g. for:

o Competition Entries

o Voting

o Polling

o Lobbying

o Petitions

anonymous but verified login

to create a profile blacklist e.g. to provide Anti Touting

authentication without usernames + passwords

· form filling / registration

Send a user's identity over the Internet

restricting access to content by:

o Location

o Age

o Nationality

o Name

o DOB

o Address

o other 'profile' details

· Enabling paywalls to work more effectively by associating users with probable desired content, either through expressed interest or attributes.

• Subscription Services

Streaming content for specific user access, for example User "A" who is a BBC licence payer is able to access the content that they have paid for from France or any other country. Netflix and other companies are struggling with mobile users access rights without using geolocation as a filter.

F2F P2P (Friend to Friend/Peer to Peer)

The uPass system can be configured in an F2F context. This can work both in a face to face via a QR code /NFC scan and also remotely by sending a link through a messaging platform.

For example is can be configured to provide mechanisms for the following:

• Entry to a building via QR code / NFC

o Company

o Age

o Nationality o Name

o DOB

o Address

o Do you have the correct ticket

o Do you have the correct security clearance

o other profile details

• Proving age for access control / point of sale, for example at:

o Nightclubs

o Casinos

o Pubs

• Simultaneously paying for an item while proving an aspect of identity using the Yoti e-wallet e.g. over 18

• Signing into a location, for example in the following contexts:

o Roll Call e.g. schools

o Visitor Book

o Courses

o Health and Safety

o Hotels / BnBs

o Gyms

o Hospitals/ Doctors Surgery

o Offices

o Shopping Malls

o Airports

• Logging hours worked

· Hotel use case - book via connect, assign pass to device, avoid check-in + key cards

• Proving ID to another individual, for example in the context of:

o Classifieds

o Dating

o Taxis

o Flatshare

o Carshare

• Business proving ID to an individual - e.g:

o for use during home visits:

o for showing to employer

o for showing appropriate qualifications

• Individual proving ID to business, for

example:

o Pawnbrokers

o Car Rental

o High Value Purchases

o Age Restricted Goods

o Goods collection

o Transport

Proving that you are over the required age at point of purchase when buying alcohol, cigarette or any age restricted product. Not only does the purchaser conveniently purchase the goods that they require but the vendor will also receive an immutable receipt proving that age was check and who made the purchase.

• Home Delivery, for example to provide:

o Proof of Receipt of Goods

o Authorisation to individuals to collect goods on your behalf o Secure access to a storage unit via connect

• F2F and online KYC, e.g. in the context of:

o Estate / Lettings Agents

o Creating bank accounts

o Insurance

o Mortgage

o Peer2Peer lending

o

• Employee proving ID to business, for example demonstrating:

o Right to work inc.:

^■ Visas

^■ Qualifications

- Nationality etc

o User Access to Business Applications

o Building Access

o Certifications e.g.:

^■ Health and Safety Course

^■ Forklift Driver

^■ First Aid

^■ Child Protection

- CRB/DBS

^« License to Practice

■ Insurance, e.g.:

• Indemnity Insurance

• Liability insurance

Yotis issued by third parties

Examples of third parties that can usefully issue Yoti's are:

• Parents

• Businesses

• Charities, e.g.:

o Disaster relief - charity can issue a temporary identity until such a time when the country's infrastructure has improved

• Yoti portal allowing merchants / vendors / businesses etc to set up a Yoti company profile. From there they can assign attributes and their staff, customers etc that will grant them rights or authentication. This might manifest in gas man and seasonpass

Global address book

• Yoti will allow a profile of attributes to be not only share with multiple people but also be revoked as and when you wish it to be.

• As such users will not ultimately need to keep their own contact directories, rather a global address book will exist with dynamic up to date attributes with with a nexus of permissions that exist between users.

• Sharing a user's contact information with others which gets updated when the user updates

• Being able to restrict access to your contact information

• Sharing business cards

VRM (Vendor relationship management)

Yoti is an enabling technology could realise the visions of Doc Searls and others. In essence, through a certified, secure and trusted identity and digital vault (see below) one could:

• Public release data about oneself that expressed a wish to purchase something, what you would be willing to pay for it, and some terms under which you would be willing to trade.

• Vendors are then able to respond to those terms with offers.

A protocol that defines the manner in which the these terms are broadcast, consumed and responded to needs to be established.

A forum in which opportunities can be searched and responded to needs to be established. Applications that deliver the above need to be developed.

Digital Vault

• Applications that use a trusted identity as a mechanism to access and control a store of personal data.

• Applications where attributes can be held securely and encrypted.

• Personal vault linked to identity, e.g. for:

o Documents

o Qualifications

o Digital Content

o Medical records

o Wills

o Share Certificates

• Cryptographic key store - allow yoti to store keys to unencrypt secure

documents stored elsewhere Age Restricted Content & Products

• Anonymous Age Verification

• Secure Login

• Prevent Sharing of Login Details

• Age Restricted Chat Rooms

• Children's Games

Applications

Asset Tracking

Either through tags to physical objects or through virtual devices and node we can associate identities to assets.

• Applications that aid the association of identities and policies to assets.

• Applications that control a register of assets with their identities and policies

• Assigning an identity to an object

• Assigning useful Yoti attributes to RFID tags, QR codes and other unique

identifiers that when consumed give out useful data. For example a lost wallet with an RFID tag with personal attributes can be scanned and data delivered that the finder can contact and return the item.

• Digital watermarks

o Assigning an identity to digital content

o Assigning an identity to tickets

• Tagging pets

• Assigning an identity to

o Certificates

o Documents

o Share certificates

IOT (Internet of Things)

• Assigning permissions to loT connected devices based on a Yoti identity

• Allowing devices to communicate with individuals

• Payment to systems via the ewallet (e.g. accessing an autonomous vehicle)

• Providing a security layer to devices. Any IOT device can ensure that

authorised users can access and control it. Both the device and the user have been given an identity via Yoti and as such permissions can be controlled.

• Applications that deliver functionality as above Microdonations

• Provision of payments through an application where regulations have been met and the transaction charge was negligible and therefore worthwhile.

Messaging system for healthcare patients and staff to give and receive feedback

• Communicate the experience anonymously or directly

• Build a database of outcomes and learning for continual improvement

Loyalty scheme

management

• registering to loyalty schemes

• proof of membership, loyalty level, points allocation

Club management

• registration to clubs / societies

• proof of age

• membership communication

• payment of subscriptions and other items relating to

club

Digital signatures

• signing electronic format contracts (like DocuSign)

• acknowledging agreement to an agreement created and hosted on

Yoti

Escrow Services

• domain name transfers

• other electronic item transfers

• physical good transfers (e.g. City exchanges) Invoices

AML (Anti Money Laundering)

• Associating identity to financial transactions.

• Associating identity to the block chains

• Providing immutable, auditable receipts to transactions conducted outside of the traditional (1850 - 2010) banking platforms, ie transactions through text messages, email, mobile payment applications etc

• Credential Management Apps - Across Devices

• Private Messaging System - Like Wickr but with a guaranteed identity

• Encrypt emails using Yoti, e.g. to provide:

o Digital signatures and encryption using Yoti identities for

permission

Ticketing & anti touting

• Verifying Identity

• Prevent Bots

• Prevent Multiple Accounts

• Control Purchasing of Tickets, ballots, age restirctions, fan base only etc.

• Blacklists

• VIP lists, promos to select members

• Tout Profiles, monitoring of tout behavior and restricting future access

• Assigning Identity To Tickets

• Purchase of Tickets (through e-wallet)

• Controlled Resale of tickets

• Event Entry Control

• Ballots

• Offer events a profit share on the resale of tickets

• Delivering tickets though a blockchain

• You face is your ticket - no paper ticket nor QR code required.

• Applications that deliver functionality as above

E-Wallet

• Building an e-wallet on top of an identity system • Social Savings

• Pocket Money / Childrens ewallet, parental control and oversight with a simple mechanism to add funds.

• P2P Payday lending

· Charity Donations

• Associating profiles with contactless payments

• Cryptocurrencies

• Tying in identity with cryptocurrencies

• Secure Ledger , e.g. for managing:

o Cyrpotcurrency - removes need for distributed ledgers

• Microdonations

• Transferring funds

Transferring identity details along with payment e.g. transfer age, gender along with the payment to a vendor

Lettings Applications

D Overview To provide a digital and streamlined alternative for tenants, landlords and letting agents to check identities, employment, residency and credit histories, referencing to ensure compliance to all current legislation.

Know Your Customer - Validate the identity of tenants, to confirm, full name, nationality, date of birth, current address (3 years history), bank account validation. To include right to rent checks (EEA passport or identity card, permanent residence card or travel document showing indefinite leave to remain, Home Office immigration status document, certificate of registration or naturalisation as a British citizen. Credit Checks - to include Credit Check Acceptability Score, credit history search over a six-year period, County Court Judgments (CCJs) & bankruptcy checks, individual voluntary agreements and/or debt management plan information, debts, defaults, rent arrears and repossessions checks.

Employment Verification - Proof of employment (at least 2 years), name of company, contact details, start date, annual salary (inc overtime and bonuses), probationary period. Business accounts if self employed.

Previous employment details, name of company, contact details, start date, annual salary (inc overtime and bonuses).

Previous landlord - Reference from current landlords or letting agencies - Name, contact details of agents/landlords and address and dates of everywhere you have lived in the past 3 years Rent guarantor's - for students or young people renting for the first time, or you can't prove that you can pay the rent. The guarantor will have to sign a document agreeing to pay the rent if you do not.

Guarantor would usually need to be a UK resident and own a property

Website Page and Requirements

Website URL

Yoti Login

Tenant

• Full Name

• Nationality^*

• DoB

· Current Address

^*lf not UK, EEC + Switzerland

UK Visa (Residency permit etc)

Chip

Security Features (where chip not present)

Credit Check (up to 6 years history)

• Credit score

• Tenant affordability

· Linked address

• CCJ

• Electoral Roll

• Insolvency

User has to consent to credit report taking place

Current Employer:

• Name of Company:

• Address of Company:

• Contact: First Name Last Name

· Email Address: (x2)

• Phone Number:

• Employee Start Date: Day (option) Month & Year (mandatory)

• Employee End Date: Day (option) Month & Year (mandatory)

• Job Title:

· Annual Salary:

• Probation Period (tick box):

Previous Employer (if current employment less than 2 years)

• Name of Company:

· Address of Company:

• Contact: First Name Last Name

• Email Address: (x2) • Phone Number:

• Employee Start Date: Day (option) Month & Year (mandatory)

• Employee End Date: Day (option) Month & Year (mandatory)

• Annual Salary:

Employer Reference

Receive email with link

• Log in - Username & Password (get Yoti, signs in with Yoti?)

• Confirms tenants details:

o Employee Start Date: Day (option) Month & Year (mandatory) o Employee End Date: Day (option) Month & Year (mandatory) o Job Title:

o Annua! Salary:

Tick box to confirm - By completing this reference you are agreeing that you are authorised to provide this information, it is an offence to supply a fraudulent reference. This reference will be used as part of our assessment of the above named persons application. In line with the Data Protection Act 1998, if requested, a copy of your reference may be supplied to the above named persons and/or the client we are acting on behalf of. I declare that the above statements are true and complete to the best of my knowledge and belief, and that no material facts have been withheld, suppressed or omitted.

Previous Landlord/Agency Reference (Past 3 Years)

• Landlord/Agency Name:

• Contact Person: First Name Last Name

· Email Address:

• Phone Number:

• Previous Address:

• Tenancy Start Date: Day (option) Month & Year (mandatory)

• Tenancy End Date: Day (option) Month & Year (mandatory)

· Comments:

o Arrears

o Damage

o AOB

• Full Name

• Nationality (must be UK resident)

• DoB

• Current Address

• Name of Employee:

• Address of Company:

• Contact: First Name Last Name

• Email Address: (x2)

• Phone Number:

• Employee Start Date: Day (option) Month & Year (mandatory)

• Employee End Date: Day (option) Month & Year (mandatory)

• Job Title:

• Annual Salary Where an applicant tenant selects time at current employer as under 3 months, the site should request that the tenant completes a Guarantor details section. Credit report etc. should then be obtained for the Guarantor instead of the applicant tenant.

Guarantor also required where salary is too low or bad credit rating/criteria is obtained (lettings Agent should be able to select their own thresholds for this to automate the system and require guarantor in advance to reduce back and forth.

Where guarantor is required, we can offer the deed of guarantee agreement as part of the package. Currently, this is done by the letting agent rather than the tenant referencing company.

Reception Applications

What is Yoti Reception?

Yoti Reception is a digital alternative to a paper-bound visitor book. It is much more adaptive than a non-digital solution that allows office buildings to notify inhabitants when they have a visitor, while improving security via digitally ID'ing visitors.

What problem is Yoti Reception trying to solve?

Yoti Reception is a solution to multiple problems that have been detailed below:

How are the problems typically deait with at present?

The current solution implemented by the majority of buildings is to require visitors to sign their name and details into a paper bound log-book held in reception.

Why will Yoti Reception be an improvement? • It will notify the appropriate person that there is a visitor waiting for them, reducing the time in which visitors have to spend unattended in a building foyer

• It can log details in a digital format that is easily accessible and traceable at both a company level, and at a building level

• It will integrate with Yoti's ID functionality - giving buildings and companies the peace of mind that individuals who enter their building 1 ) can't lie about their identity and 2) are held accountable by recording their actual identities

Will there be any requirement for a. visitor to present ID, and if not, y not?

No, this is because the service is primarily a streamlining solution that enhances the visitor experience rather than a security enhancement. Requiring visitors to presents their ID increases friction within the transaction. In future buildings could disable the email sign-in

Nightclub Applications

An identity system that is used in places where businesses are legally required to check the identity/age of individuals in real life.

People are used to presenting identity before entering a venue that serves alcohol, meaning they are going to expect to use their Yoti here, whether we offer this product or not. This document is setting out the general strategy for this sector.

Yoti is an identity system that can be used on and offline.

1.1 Problems we are solving

Problem Solution

Carrying around documents Yoti is on an individual's phone

Employees not trained to identify Yoti verifies documents and information before fraudulent documents displaying this to businesses

No safety aspects to manually We provide venues with a record of who has looking at a passport entered their venue

The lengthy process venues go to One QR scan and we can share data with these get data venues Duty Free and tax refunds

Using technology to simplify the international tax refund schemes which are complex to understand time consuming to operate. In addition there is a great deal of error from applicants and the tax authorities which is costly to rectify. The combination of Yoti identity on a phone, in conjunction with the attributes of the visa allowing the foreign national to be eligible for tax free shopping in the country and with the use of ewallet that transacts these payments, our application will:

For individual

• ID individual

· From passport classify their nationality

• From ViSA classify them as category 1 , 2 or 3

• Present them with and explanation of the benefits of what they can benefit from and the stores from which they can accrue this benefit.

• Make them confirm the terms and conditions of the the rebate both for HMRC and also to accept and charges that the store may wish to apply to this process

• Make a payment from YotiWallet or an alternative for the full payment

including VAT.

• Add the item/s purchased to a basket of qualifying items purchased and

display a possible rebate value to be reclaimed upon successful confirmation at customs.

For HMRC border staff or authorised Mi Pass staff

• ID the individual standing in front of them

· Record the date they are exiting the EU (Ticket / Boarding card etc)

• Provide a checklist of all the items that are being claimed against so the staff can choose to check / verify.

• Certify the export is correct For the merchant

• Yoti check that the individual is who they say they are and confirm that they qualify for the scheme.

• Mandate the acceptance of the scheme and store admin charges and sign the agreement from both parties.

· Take a payment from YotiWallet or an alternative for the full value including VAT.

• Merchant dashboard should display the total purchases of all qualifying items that are awaiting confirmation at customs and those that have already been approved and refunds due to be paid back out to individuals MiWallet account.

For the tour group leader

Link all individuals associated to their group and track their purchases in each store so that they might benefit from the commission. SECTORS

MOOCs / Training

• Online tests, e.g.

o Random face checks to verify identity

o Verify identity of examinee

o Checking Identity of Examiners

o Assigning qualifications

o Secure Login

o Applications that deliver the functionality above.

Freelancers

• Verifying Previous work e.g. associate identity to previous designs

• Reviews

• Prevent multiple accounts

• Payments (through eWallet)

• Verifying qualifications

• Establishing a contract between 2 parties prior to coming on site. For example a plumber may specify a call out charge and time at £x and materials as their terms and a the purchaser will accept these terms before the plumber departs for the job. Equally the purchaser will expect that quality work will be conducted and will sign off that the work has been conducted to suitable standard. Therefore, reduced ambiguity and happy parties.

• Applications that deliver this functionality.

Sharing Economy

B2B (Business to Business)

• Verifying Users

• Assurance of identity in an immutable record should something nefarious or unfortunate take place.

• Verifying ownership of shared goods

• Registration / Login

• Payments (through ewallet)

B2C (Business to Consumer)

o Allow users to send identity to each other over the internet

o Allow users to show identity in person Classifieds

• Verifying Users

• Verifying ownership of goods

• Registration / Login

• Allow users to send identity to each other over the internet

• Allow users to show identity in person

• Payments (through ewallet)

• Improved safety from knowing who you are dealing with

• Reduced fraud from knowing who you are dealing with.

• Reviews that can be trusted

• Applications that deliver the functionality above.

Online Dating

• Verifying Users

· Prevent Bots

• Prevent Multiple Accounts

• Registration / Login

• Allow users to send identity to each other over the internet prior to

meeting. Increasing trust decreasing deception.

· Allow users to show identity in person

• Providing immutable record of identity exchange.

• Temporary Chat

For Example

An individual is able to register themselves on the site using verified

information. This would prevent users creating completely fake profiles, creating multiple profiles or lying about details such as age.

Before going on a date the two individuals will be able to send their identity to each other using a link through sms/email or another chat function so they both know who they are going to be meeting. Then when they do meet up in person they would be able to do another interaction using the system giving them both a timestamped receipt of meeting up so if anything happened both parties would be able to confirm exactly who they met with and when.

Online Gaming

. AML

. KYC

• Prevent Bots • Eliminate robots that are rigging games and cheating human players

• Prevent Multiple Accounts

• Secure Login

• Payments (through ewallet)

DRM Content Management

• Assign Identities to Digital Goods

• Allow resale of digital goods through Yoti

Ticketing / Events / Conferences

• Verifying Identity

• Prevent Bots

• PRevent Multiple Accounts

• Control Purchasing of Tickets

• Blacklists

• Tout Profiles

• Assign Identity To Tickets

• Purchase of Tickets (through e-wallet)

• Controlled Resale of tickets

• Event Entry Control

. Ballots

Third Sector

Review Sites

• Prevent Bots

• Prevent Duplicate Accounts • Prevent Fake Reviews

• Secure Login

• Verifying Businesses

Public Health

• Verifying Employees

• Verifying Visitors

• Storage of I Patients Health Records

• Asset management

• Building Entry

• Doctor Patient Messaging

• Patient Feedback

• Online Appointment Booking

• Bedside secure access to records for medical professionals

• Patient access to medical records

• Patient access to booking appointments online

Delivery Services

· Verifying Identity of Individuals Picking up parcels

• Giving friends/family permission to pick up parcels on your behalf

• Signing for Parcels- Receipt of Delivery

• Verifying employees

• Asset Management, e.g.:

o Employees signing out vans/cars

Insurance

Disruption to the insurance by using Yoti connect and face to face as a mechanism to:

· Verifying ID more expediently, cutting the time required to accurately establish if a potential is who they claim to be.

• Having verified identity expediently to a very high level, risk can be better judged, and premiums positioned to the desired level.

• Insurance fraud can be reduced.

· Applications can be developed that quickly align individuals to policies

• Applications can be developed that allow those seeking insurance to expose their profiles to providers.

• Issuance of certificates to be stored as a shareable attribute in the Yoti system. Recruitment

• Verifying Identities of candidates, e.g:

o Qualifications

o Visas - checking their right to work

o Nationalities

• Sharing identity with HR

• Sharing contact details

Details can either be shared in person - via a face to face check, or they can be shared remotely - via company specific Webpages, containing QR codes that are communicated to applicants via email or via website integration

• Discounts Based on profile items

• Loyalty Schemes

• Proof of membership

• Proof of age

• Competitions

• Data Capture of shoppers

. EPOS

• Building Access

• Online Retail Login

• Online Retail Registration

• Payments (through eWallet)

Company Profiles

• Business proof of identity to customer on home visits

• Proof of qualifications to customer

· Proof of receipt of visit

• Proof of work done

example British Gas may wish to issue a credential / profile to one of their employees who can show this to homeowner. The homeowner will see the photograph of the Gas operative which is issued and therefore certified by the gas company. Both parties will receive a receipt of the exchange. British Gas can view employees activity log and GPS location. Residential

• Proof of right to live

• Contact sharing

• Landlords running affordable KYC and credit checks on a potential tenants before investing time to show them round.

• Tenants broadcasting a profile explaining what their budget is and what they are looking for in order to receipt offers.

Financial Services

. KYC

• Quick registration

. AML

• Secure online login

• Disruption to the insurance by using Yoti connect and verifying ID we can mitigate false insurance, creates a lower premium due to lower risk due to a verified identity

• Unique QR code on envelope or internal document, scanned using Yoti to (biometrically) confirm receipt by intended recipient

• Building Access

· Activating Cards, remote authorizing / verifying cards. Which codes printed on cards we can ask user to scan the code to confirm that it is them using it (for example when a bank freeze your card when abroad and asks you to call them back for fraud prevention). By scanning a code on receiving the card you can activate it.

· ATM withdrawals, in the future this can be identifying oneself with no need for a cash card.

• Onboarding customers and connecting their biometrics to a banking

application in one transaction

• Once a card has been verified as received by a Yoti user, we may record a unique card attribute against this user within their secure set of Yoti attributes. Upon request a user can confirm that they are not only the user that is expected in the transaction but also that they are in possession of the unique card attribute. This can replace card authentication processes such as 3DSecure, Verified by Visa and any other such schemes that are giving the card issuers confidence that the card is be utilised by the authorized person. A typical use case would be when making a purchase of goods or services online using a credit card and being asked to make an additional authentication. Overview of Yoti for Financial institutions: Desktop customer AML level checks against verified identity documents that have Onboarding been biometncally linked to an individual

Mobile customer AML level checks on a against verified identity documents that onboarding have been biometrically linked to an individual. All carried out on a mobile phone - this can include Yoti creation through our SDK

IV!FA Authentication linked to a person's verified biometric information,

Authentication device and passcode

Connecting bank Connect a bank account/card to Yoti so that the individual can card to identity then use their card through Yoti QR codes

Reset Through taking a selfie a person can biometrically authenticate passcode/order themselves if they have lost their card and/or forgotten their new card pin/password, the card could then be sent out like below

Bank card Prove that a person has received a bank card through the post authentication by scanning a static QR code on the letter or on the card itself, this static QR code requests the name of the individual to verify that the right person has received the card

Universities

• Building Access

• Secure online login

· Receipt of work Submissions

• Verifying identity of students

• Verifying Visas

• Payments (through ewallet)

• Library book loans

· Club / Society Memberships

• Age Verification at Bars

• Roll call for lectures/seminars

• Storing University Certificate qualifications digitally

• Student discounts and offers

· Applying for student loans

Airlines

• Purchasing the flight ticket via Yoti ewallet and simultaneously attaching all ID details to the ticket • Proving identity while purchasing the flight ticket and attaching this ticket to a Yoti

• Connecting boarding pass to identity

• Storing the boarding pass on Yoti

· Proving your identity and proof of purchase simultaneously at the airport

• Working with airlines, airports and the border authorities to expedite

passengers securely through high security areas

• Applications that deliver the functionality above

Travel

• Storing Tickets

• Proof of age for discounts

Public Sector

• Voting and Polling - Online and Offline

· Asset Management

• Creation of immutable public records that hold identity, ie the land registry, etc.

Adult

The adult sectors is insufficiently regulated and therefore people under the required age to access adult content are often easily able to do so when gaining access to unrestricted internet. Governments are stating that they will instigate change but are lacking tools to do so other than insisting upon ISPs to block providers who do not acquire Credit Card details or ID documents as proof of age. Yoti will enable users to anonymously certify that their are over the required age, giving no names, DOB, address or other attributes. By using the Yoti API an adult site can simply as a response from Yoti to a question eg: "Is this person over 18"? The Yoti validation service will reply "Yes" and given them an anonymous receipt to confirm they have reach the required government standard.

Additional use cases are set out in tables 1 and 2 at the end of the Detailed

Description.

Whilst the above has been described in terms of specific embodiments, these are not exhaustive. The scope is not limited by the described embodiments but only by the following claims. TABLE 1 :

Proof

that a

example real ano proof of

organisation log in perso proof of nym address conta

Sector s and reg n age ous ct details specific use case

Glastonbury / stop bots buying tickets / know who

Events and Rugby World is in your venue for H&S

ticketing Cup / U2 yes yes yes requirements / check age

Autotrader / Allowing users to check ID of

Classified Gumtree / buyers/sellers to assure they're not sites Freecycle yes yes yes going to rip each other off

Match.com /

Single easy return log in for regular usage / Muslims / stop users lying about themselves / Guardian stop sites using bots to lure punters

Dating sites Soulmates yes yes yes yes in

Give hosts/guests assurance that

Peer-to-peer users are not villains / give guests accommodati Airbnb / assurance that house belongs to on Roomshare yes yes yes host

Give drivers/passengers assurance that users are not villains / give passengers assurance that car

Peer-to-peer Bla Bla Car / belongs to driver and they have a car sharing Go Car Share yes yes yes valid licence etc

Freelancer.co Assurance that people you are

Peer-to-peer m / chat talking to are a) real people b) have other... rooms yes yes yes yes the age/gender etc they describe

Jackpot Joy / Check users are over 18 (or 16) / online Pokerstars / stop people cheating by setting up gambling Lotteries yes yes yes yes yes multiple usernames

Playboy / Check users over 18 / give adult sites tube sites yes yes yes yes yes anonymous log in

Check users are not pretending to be children (i.e. grooming) and stopping cyber bullying because children/youth bullies can't hide behind fake specific sites Club Penguin yes yes yes yes profiles

ASOS / Allowing retail outlets (both online Topshop / and f2f) to offer age/gender or even

Retail outlets Starbucks yes yes yes yes name related offers

building entry / borrowing library

Student NSU / books / discounts specific to that uni bodies Universities yes yes yes / entry to bars and clubs etc

age and/or gender restricted areas

UK Youth / of websites / online polls / assigning Oxfam / Oxfam Yoti profiles in emergency domestic situations to act as a temporary ID

Charities and violence doc - probably with NFC chip rather not for profits charities yes yes yes yes than phone

allow start-ups to build innovative tech start solutions that are reliant on yoti developer/tec hubs / technology and will in turn deliver h community incubators yes yes yes yes yes additional use cases

Funding Proving the 'fundee' is legitimate

Fintech Circle / and not going to run off with the organisations Seedrs yes yes yes cash without delivering

estate agents and 'viewers' proving

Lettings and ID to one another (with an audit estate agents Foxtons... yes yes yes trail) to increase safety / estate

agents using Yoti as proof of ID instead of requesting paper docs etc (recognise not currently legal)

Engineers proving who they are to customers (and vice versa) / engineers proving to employer they

Utility were at location (due to audit trail companies British Gas yes yes yes given by our 'receipts')

using NFC phones (and chips) as building Hotel chains / passes to enter buildings and rooms entrance office blocks yes yes yes (e.g. in hotel chains)

similar to above but a simpler version that just links NFC reader to a tablet to show picture of user when they swipe with Yoti chip (could be used at reception) . This will be be particularly relevant in India where security is of paramount importance at the moment and current security solutions v onerous. Can also be used for checking in and out, timesheets for project based work etc. Can also be used anyone from at beginning of employment to verify Lampkicking they are who they say they are, employers to Deloitte... yes yes yes yes maybe even visa requirements etc allow users to post anonymously

Health forums when the subject matter may be discussion / political personal and to prevent

forums commentary yes yes yes racial/sexual bullying etc

broadcast and allow broadcasting and streaming streaming companies to better manage their content Sky, Vivendi, clients, avoiding password sharing, websites Netflix, BBC yes yes yes yes etc.; eventually allow users to use

their paid subscriptions abroad

(subject to broadcasting rights)

allow small clubs to manager their membership list, sending

communications via yoti and

attributing profiles to their members;

allow companies to issue loyalty

digital 'cards' via yoti, sharing

membership communications and promotions;

details & allow users to store all membership loyalty and loyalty programme details on multi sector programmes yes yes yes yes their yoti

digital

"ownership"

of company manage company assets, allowed assets and staff users, control which equipment "usage" by an is held by each staff member mu!ti sector employee (hardware, software)

TABLE 2:

Age / Relevant Industry & Milestone uPass Cases Information Sector Target

Attending

Nursery

Maintain

Medical secure medical

(Age 2-4) Information Allergy advice, injections record Parents

Safe picks ups Who can pick child up Nurseries

First

passport

School

Parents topping up account, setting limits The end of

on amount child can spent and see what payment

(Age 5-18) Lunch money they are spending money on hassle

Parents agrees for child to attend trips,

Trip money sends money for trip

Parents being able to see location of

children (maybe up until a certain age

Geo-location age)

Individual attends exams (although

usually phones aren't allowed in exam

Exams rooms)

Prove

Exams Results Link exam results to uPass qualifications

First bank

account

Travel pass

Set up Social End of

Networking username and

Sites passwords

End of

username and

Online Games passwords

Children Chat Proving they are the correct age to enter Eliminating

Rooms the chat room grooming

Sending The end of

money to payment

friends hassle

End of

username

Prove and

CV Job application, job sites qualifications passwords

Corporate

Work - part- logon /

time authentication

Learning to

drive

End of

University username

Application Prove and

(UCAS) qualifications passwords

Buying Age

restricted

goods (offline Easy online and online) age check

Cinema - Easy face to proving age face check

Eliminating

Buying Tickets Touting

Receiving The end of

money from payment

parents hassle

Maintain

Medical secure medical Information record

Second

passport

University

Prove

(Age 18-21 ) Exams Attendance and proof of results qualifications

End of

username and

University passwords

Access / Login (Uni website)

Using taxis

Student Loans Application

End of

username

and

passwords

Proof of age (student

Student (student discount

Discounts Proof of student status status) sites)

Buying Age

restricted The end of

goods (offline Easy online payment

and online) Alcohol etc. age check hassle

Easy face to

Entering Clubs face check

The end of

Eliminating payment

Buying Tickets Touting hassle

Sending The end of

money to payment

friends hassle

Receiving The end of

money from payment

parents hassle

End of

username

and

passwords -

Insurance

Insurance (Travel, Contents, Car) sites

End of

Eliminating Eliminating username scammers / bot / fake and

Online dating fake accounts accounts passwords

Adult sites / Easy online End of

films age check username

and

passwords

End of username and

Trading Items Buying and Selling online passwords

Parcel delivery

and pick up (Proof of delivery and pick up) Free secure ID

Part-time work Corporate

/ Work Prove logon / experience Applications, references qualifications authentication

Free Digital

Register for democracy for voting all

Online

fundraising

Proof of

Accomodation (Proving exempt from Council Tax) student status

Corporate

logon /

Volunteering authentication

End of username

Job Entering details, logging into job / CV Prove and applications sites qualifications passwords

Maintain

Medical secure medical Information record

Post

Student

CRB / DBS

(22+) Checks

Work - entering Corporate

company logon /

buildings authentication

Prove Easy face to

Work - HR Proof of ID, CV / qualifications qualifications face check

Car Rental

Insurance (Home, Pet, Travel, Contents, Car)

Professional Prove

Exams (Proof of results) qualifications

Using taxis

Third

passport

Mortgages /

Financial Eliminating ID

Services fraud

News /

Website

Subscription Micropayments

End of

Donating to payment

Charity Micropayments hassle

Eliminating

Adult Chat Easy online scammers / Rooms age check fake accounts

End of

Eliminating usemame scammers / Easy online and

Dating Sites fake accounts age check passwords

Register

Council Tax

Maintain

Medical secure medical

Records record

Eliminating

Buying Tickets Touting

Loyalty

Programmes

Parcel Delivery

/ Pick Up (Proof of deliver / pick up) Free secure ID

End of

End of username

Online payment and

Shopping (Proof of delivery) hassle passwords

Home care - Know who is entering your home - their Doorstep Prove Cleaner ID, experience etc. villains qualifications

Home care - Doorstep Prove Decorator villains qualifications

Home care - Doorstep Prove Builders villains qualifications

Important Docs Signing digital (uPass Vault) Insurance documents

Asset

management

Large Purchases (receipts) with insurance

Passwords

Driving License

Asset

management

Financial Info, Shares with insurance

Eliminating ID

Store Card Details fraud

Digital

Signature

Access to nursery, allowed to pick child

Parental Duties up from nursery / school

Nanny / childcare vetting

Child trust funds

Retirement

Pension

Travel passes

Health Profile Medical Information

Emergency

Contacts

Asset

Important Docs management Signing digital (uPass Vault) Will, estate information with insurance documents

The end of

Online payment

shopping hassle

Eliminating

scammers /

Online Dating fake accounts

Gambling Sites

Access to

community

services

Financial Eliminating ID

Information Stocks and shares fraud

Insurance

Claims

Claims:

1. A method of authorizing a secure electronic payment from a payer to a payee, the method comprising:

receiving, at a digital identity system, an electronic message, which comprises a payer credential and identifies a payee system;

at the digital identity system, accessing a digital identity associated with the payer credential, wherein the digital identity comprises:

1 ) at least one identity attribute or data for deriving at least one identity attribute, and

2) a payment token or data for obtaining a payment token, the payment token for effecting an electronic payment from the payer to a recipient of the payment token; and

transmitting at least one electronic message from the digital identity system to the payee system to render the identity attribute and the payment token available to the payee system, for determining, based on the identity attribute rendered available to the payee system, whether to use the available payment token to effect an electronic payment from the payer to the payee.

2. A method according to claim 1 , wherein the electronic message comprising the payer credential is received from a device of the payer.

3. A method according to claim 1 , wherein the payee system is identified by a payee credential comprised in the message and associated with the payee system.

4. A method according to claim 3, wherein the electronic message comprising the payer credential and the payee credential is received from a device of the payer, the payee credential having been captured at the payer device

5. A method according to claim 4, wherein the payee credential is in the form of a sharing token issued to the payee by the digital identity system in response to a request from the payee.

6. A method according to claim 5, wherein the payee sharing token is associated with a policy, which indicates a type of the identity attribute to be shared with the payee and indicates that the payment token will be shared with the payee.

7. A method according to claim 6, wherein a copy of the policy is cached at the digital identity system in association with the sharing token, wherein the transmission of the at least one electronic message is conditional on a matching policy being received from the payer device with the payee sharing token.

8. A method according to claim 6, wherein the policy is displayed at the payer device when the payee sharing token is captured.

9. A method according to claim 4, wherein the payee credential is captured from a barcode or QR code presented to the payer.

10. A method according to claim 9, wherein the barcode or QR code is displayed on a display of the payee system for capturing by the payer.

1 1 . A method according to claim 1 , wherein the payment token is obtained from card details or bank details of the payer.

12. A method according to claim 1 1 , wherein the card or bank details are stored as part of the digital identity, and the stored details are used by the digital identity system to obtain the payment token.

13. A method according to claim 1 , wherein the payment token or the data for obtaining the payment token are stored at the digital identity system in an encrypted form, such that at least one payer key is required to decrypt them, wherein the payer key is provided to a device of the payer and is not retained at the digital identity system, wherein the method comprises receiving the at least one payer key from the payer device and using it to decrypt the payment token or the data for obtaining the payment token.

14. A method according to claim 13, wherein the payer key is provided to the payer device in an encrypted form, such that a payer wrapper key retained at the digital identity system is required to decrypt it, wherein the payer wrapper key is not released outside of the digital identity system.

15. A method according to claim 14, wherein the payment token or data for obtaining the payment token is held in a database of the digital identity system, wherein at least one database key for locating the payment token or data for obtaining the payment token in the database is provided to payer device, wherein the at least one database key is received from the payer device with the at least one payer key and used to locate the payment token or data for obtaining the payment token for decryption.

16. A method according to claim 1 , wherein the identity attribute is an age-related identity attribute for determining whether the payer meets an age requirement before effecting the electronic payment.

17. A method according to claim 16, wherein the payee system is embodied in a self-checkout terminal and the self-checkout terminal uses the identity attribute to determine whether the payer meets the age requirement.

18. A method according to claim 1 , wherein the identity attribute is a name, or a facial image or other biometric identifier of the payee.

19. A method according to claim 1 , wherein the payment token is obtained independently of a trusted source of identity information to which the identity attribute is anchored.

20. A method according to claim 1 , wherein the identity attribute is a data item captured from an identity document.

21. A method according to claim 20, wherein the identity document is a passport, driving license, or other national identity document.

22. A method according to claim 21 , wherein the identity attribute is verified by comparing a biometric identifier captured from the payer with a biometric of the identity document.

23. A method according to claim 1 , wherein the payment token is bound to an identifier of the payee, such that it can only be used by the payee.

24. A method according to claim 1 , wherein the payment token is a one-time use only payment token.

25. A method according to claim 1 , wherein the electronic message transmitted to the payee device is in the form of a receipt, wherein a second receipt is transmitted to a device associated with the payer credential.

26. A method according to claim 25, wherein the second receipt comprises at least one identity attribute of or derived from a digital identity associated with the payee credential.

27. A method according to claim 25, wherein the receipts include matching transaction identifiers.

28. A method according to claim 1 , wherein the payer credential is a one-time use only credential, and the method comprises transmitting a fresh credential to a device associated with the payer.

29. A method according to claim 1 , wherein the payer credential is validated at a validation service of the digital identity system, and the transmission of the at least one electronic message is conditional on the credential being valid.

30. A method according to claim 1 , wherein the electronic message comprising the payer credential is received from the payee system, the payer credential having been captured at the payee system.

31 . A method according to claim 30, wherein the payer credential is in the form of a sharing token issued to the payer by the digital identity system in response to a request from the payer.

32. A digital identity system according to claim 1 , wherein the identity attribute is an anonymous identity attribute.

33. A digital identity system according to claim 1 , wherein the electronic message transmitted from the digital identity system to the payee system comprises a link to a memory location at which the identity attribute and the payment token are published, thereby rendering them available to the payee system.

34. A method according to claim 1 , wherein a biometric authentication is performed by comparing a biometric identifier captured from the payer with biometric data of or associated with the digital identity.

35. A method according to claim 34, wherein the identity attribute comprises the biometric data for performing the biometric authentication at the payee system.

36. A method according to claim 35, wherein the at least one electronic message also renders available to the payee system an age-related attribute of or derived from the digital identity.

37. A method according to claim 34, wherein the biometric identifier is captured at the payee system and provided to a device of the payer for performing the biometric authentication at the payer device.

38. A method according to claim 1 , wherein the payment token is an

authentication token for authorizing the electronic payment via an API.

39. A method according to claim 1 , wherein the payment token is a token for authorizing a cryptocurrency transfer.

40. A non-transitory computer readable medium having executable instructions for authorizing a secure electronic payment from a payer to a payee, the instructions configured, when executed at a digital identity system, to implement the following steps:

receiving an electronic message, which comprises a payer credential and identifies a payee system;

accessing a digital identity associated with the payer credential, wherein the digital identity comprises:

41 . A digital identity system comprising:

a computer interface configured to receive an electronic message, which comprises a payer credential and identifies a payee system;

at least one processor configured to implement the following steps:

1 ) at least one identity attribute or data for deriving at least one identity attribute, and 2) a payment token or data for obtaining a payment token, the payment token for effecting an electronic payment from the payer to a recipient of the payment token; and

transmitting at least one electronic message from the digital identity system to the payee device to render the identity attribute and the payment token available to the payee device, for determining, based on the identity attribute rendered available to the payee device, whether to use the available payment token to effect an electronic payment from the payer to the payee.