The present application is a divisional application based on a parent "method and apparatus for protecting private information", which has an application date of 2015, 12 and 23, an application number of 2015109828430, and a publication number of CN 105530261A.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
An embodiment of the present invention provides a method for protecting privacy information, where as shown in fig. 1, the method includes:
101. and the client intercepts the calling request information.
In the embodiment of the invention, the client is installed in the terminal equipment, and the terminal equipment must support the system camera program. When privacy information is protected, in order to prevent a third-party application program from calling a system camera program, a client intercepts calling request information sent by the third-party application program to the system camera program; the calling request information comprises a first preset address, and the first preset address is an address corresponding to the system camera program. Ensuring that the camera called by the third party application program is not a system camera program but a secure camera in the client; further, it is ensured that the photos or videos taken by the third party application based on the camera do not appear in the system album.
It should be noted that the calling request information includes a first preset address corresponding to the system camera program, and the first preset address may have a difference due to a difference of the system camera program; differences may exist due to different types of terminal devices; the embodiment of the present invention does not limit the specific form of the first preset address.
In the embodiment of the present invention, the terminal device may include, but is not limited to, the following contents, for example: a smart phone, a Personal Computer (PC), a tablet computer, and the like, a specific type of the terminal device is not limited in the embodiment of the present invention, as long as the terminal device supports a system camera program, and the embodiment of the present invention configures hardware of the system camera program: camera, pixel, photo resolution, digital zoom, intra-screen parameters, dynamic memory, picture editing functions, etc. are not limited.
102. And the client acquires a first preset address in the calling request information and modifies the first preset address into a second preset address.
When the third-party application program calls the system camera program, the third-party application program does not know whether the called camera program is the system camera program or other camera programs in the terminal equipment; after a client intercepts call request information, analyzing the call request information, acquiring a first preset address in the call request information, and modifying the acquired first preset address into a second preset address, wherein the second preset address is a preset address corresponding to a security camera program in the client.
In the embodiment of the invention, the second preset address in the client is unique, and the second preset address is determined and unique no matter what type of terminal equipment the client is installed on.
When the third-party application program uses the camera to photograph or record videos, the third-party application program is based on operations of photographing, video recording, privacy information sharing and the like of the safety camera in the client side.
103. And the client responds to a storage instruction sent by the third-party application program, and stores the privacy information shot by the third-party application program based on the safety camera program into a safety photo album corresponding to the safety camera program.
And after the terminal equipment user shoots the privacy information based on the security camera program, clicking a storage key in the security camera program to trigger a storage instruction. After receiving the storage instruction, the client responds to the storage instruction, and stores the privacy information shot by the security camera in a security album corresponding to the security camera; so that the terminal equipment user can access the secure album through the client. The privacy information in the embodiment of the invention comprises photos and videos.
As another implementation manner of the embodiment of the present invention, when a terminal device user determines to store a picture or a video taken by the terminal device user, a storage key in the secure camera program is triggered, and when the terminal device wants to take a picture or record a video again, a re-taking key in the secure camera program is triggered to take a picture or record a video again.
Exemplarily, as shown in fig. 2, fig. 2 is a schematic diagram illustrating a security camera program provided in an embodiment of the present invention, where when a terminal device user determines to store a photo taken by the terminal device user, a storage key is triggered to store the photo in a security album; and when the terminal equipment user determines the picture to be taken again, triggering a re-taking key and re-taking the picture based on the camera in the terminal equipment. Fig. 2 is an exemplary illustration only, and the appearance of the security camera program and the content included in the security camera program are not limited in the embodiment of the present invention.
In the method for protecting privacy information provided by the embodiment of the present invention, a client installed in a terminal device intercepts call request information, where the call request information is call request information sent by a third-party application program to a system camera program in the terminal device, where the call request information includes a first preset address, and the first preset address is an address corresponding to the system camera program; secondly, the client side obtains a first preset address in the calling request information, modifies the first preset address into a second preset address, the second preset address is an address of a safe camera program in the client side for drinking, responds to a storage instruction sent by a third-party application program, and stores privacy information shot by the third-party application program based on the safe camera program into a safe photo album corresponding to the safe camera program, so that a terminal device user can access and check the privacy information in the safe photo album through the client side; compared with the prior art that huge potential safety hazards exist in photos or videos stored in an album, the third-party application program in the embodiment of the invention shoots privacy information through the safety camera in the client, executes the storage instruction sent by the third-party application program, and stores the privacy information in the safety album in the client instead of the system album of the terminal equipment, thereby ensuring the safety of the privacy information in the terminal equipment.
Further, the client provides a plurality of service applications, including: the method comprises the steps of upgrading an application program of the terminal equipment, searching and killing viruses of the terminal equipment, recording the starting time of the terminal equipment, clearing browsing garbage in the terminal equipment, unloading the application program and other service applications, and the like, and provides favorable guarantee for the equipment safety and the running speed of the terminal equipment. In order to meet more requirements of a terminal device user, a safe camera program and a safe photo album service application are also provided in a client, wherein the safe camera program is similar to a system camera program and has corresponding preset addresses, and when the client applies the provided safe camera program and the safe photo album service, the client adds the safe camera program which comprises a photographing service and a video service; after adding the security camera program, creating a security photo album corresponding to the security camera program; and configuring a security camera program and a security photo album according to configuration information issued by the console, wherein the configuration information comprises a hidden security camera program and a security photo album, and a displayed security camera program and a security photo album.
It should be noted that after the hidden secure camera program and the secure album are configured, the third-party application program is prohibited from calling the secure camera program, that is, the secure camera program cannot be enabled. When the privacy information in the secure photo album is used, the client pops up prompt information for judging whether to start the secure camera program and the secure photo album, and the client determines whether to start the secure camera program and the secure photo album according to a selection instruction of a terminal device user. After the terminal device user determines to start the secure camera program and the secure album, the third party application may invoke the secure camera program.
Further, after the third-party application program calls the security camera program, according to the actual requirement of the terminal device user, the photographing service or the video service in the security camera program is selected, and the client records the photographing service or the video service of the security camera set by the terminal device user, so that when the third-party application program calls the security camera program again, the photographing service or the video service recorded by the client is used by default. Exemplarily, as shown in fig. 3, fig. 3 is a schematic diagram illustrating another security camera program provided by an embodiment of the present invention, which illustrates a photo service in which a terminal device user selects a set security camera program. Fig. 3 is an exemplary example, and the embodiment of the present invention does not limit a specific position of the security camera program where the photographing service or the video service is located in the security camera program.
Further, when the third-party application program needs to share the privacy information by taking a picture or recording a video, the third-party application program defaults to sending calling request information to a system camera program in the terminal equipment, and in order to ensure the safety of the privacy information, the client monitors the system camera program through a preset component and determines whether the calling request information sent to the system camera program exists or not; when the client monitors that the calling request information sent to the system camera program exists, the client intercepts the calling request information, and therefore the safety of the privacy information of the terminal equipment user is ensured.
Further, in order to further ensure the security of the privacy information of the terminal device user, before the privacy information shot by the third-party application program based on the security camera program is stored in the security album corresponding to the security camera program, the client encrypts the privacy information shot by the security camera program, stores the encrypted privacy information in the security album, and determines the security of the privacy information of the terminal device user through two layers of protection barriers. When the secure photo album is encrypted, the encryption can be realized by adopting the following modes, such as a symmetric encryption algorithm and an asymmetric encryption algorithm; for example: des (data Encryption standard), 3des (triple des), dsa (digital Signature algorithm), MD5, PKCS (The Public-Key Cryptography Standards), and The like.
Further, when a terminal device user shares hidden information with other terminal devices, the encrypted privacy information is obtained from the security album, and is sent to other terminal device users, after the privacy information is sent to other terminal device users, a client authenticates the access authority of other terminal device users, and if the authentication is successful, a secret key corresponding to the encrypted privacy information is sent to other terminal device users; and if the authentication fails, not sending the key corresponding to the encrypted privacy information to other terminal equipment users. As an implementation manner of the embodiment of the present invention, the client confirms through the device identification information of the terminal device recorded by the client, and whether the other terminal device users have the authority to access the encrypted privacy information; as another implementation manner of the embodiment of the present invention, if the terminal device user shares the private information through the third-party application, whether the key corresponding to the encrypted private information is sent to the other terminal device users is authenticated by determining whether the other terminal device users sharing the private information are in a friend relationship with the terminal device user. The embodiment of the present invention does not limit the authentication method.
Further, in order to facilitate a terminal device user to manage the privacy information in the secure album, after the privacy information shot by the third-party application program based on the secure camera program is stored in the secure album corresponding to the secure camera program, the client classifies the privacy information.
As an implementation manner of the embodiment of the present invention, when classifying the privacy information, the privacy information is classified according to a time sequence of shooting the privacy information, as shown in fig. 4, fig. 4 shows a schematic diagram of a secure album provided by the embodiment of the present invention, and in fig. 4, the privacy information in the secure album may be reordered according to a sequence of time according to a sorting key. As another implementation of the embodiment of the invention, in the safe album, the sub-albums are created and classified according to different names of the sub-albums. The implementation manner of the classification of the private information in the secure album in the embodiment of the present invention is not limited, fig. 4 is only an exemplary example, and the embodiment of the present invention does not limit the number of the keys and the private information existing in the secure album.
Further, the client responds to an operation instruction, operates the privacy information in the secure album, and operates the privacy information in the secure album, wherein the operation instruction includes any of the following contents: zooming in or out of the privacy information, deleting the privacy information, sending the privacy information, rotating the privacy information, renaming the privacy information, cropping the privacy information, and so forth.
Further, as a summary description of the foregoing embodiments, an embodiment of the present invention further provides a method for protecting privacy information, as shown in fig. 5, where the method includes:
501. and adding the safety camera program by the client, wherein the safety camera program comprises a photographing service and a video service.
502. And the client creates the safe photo album corresponding to the safe camera program.
503. And the client configures the security camera program and the security album according to the configuration information issued by the console.
504. And the client monitors the system camera program through a preset component and determines whether the calling request information sent to the system camera program exists or not.
505. And if the calling request information sent to the system camera program exists, the client intercepts the calling request information.
506. And the client acquires a first preset address in the calling request information and modifies the first preset address into a second preset address.
507. And the client encrypts the privacy information shot by the safety camera program.
508. And the client responds to a storage instruction sent by the third-party application program, and stores the privacy information shot by the third-party application program based on the safety camera program into a safety photo album corresponding to the safety camera program.
509. When the terminal equipment user shares the privacy information with other terminal equipment users, the client side obtains the encrypted privacy information from the security album and sends the privacy information to other terminal equipment users.
510. And the client authenticates the access authority of the other terminal equipment users.
If the authentication is successful, go to step 511; if the authentication fails, go to step 512.
511. And the client sends the encrypted key corresponding to the privacy information to the other terminal equipment users.
512. And the client does not send the encrypted key corresponding to the privacy information to the other terminal equipment users.
It should be noted that, for the related description of steps 501 to 512, please refer to the detailed description of the above embodiments, and the detailed description of the embodiments of the present invention is not repeated herein.
Further, as an implementation of the method shown in fig. 1, another embodiment of the present invention further provides a device for protecting private information. The embodiment of the apparatus corresponds to the embodiment of the method, and for convenience of reading, details in the embodiment of the apparatus are not repeated one by one, but it should be clear that the apparatus in the embodiment can correspondingly implement all the contents in the embodiment of the method.
Further, an embodiment of the present invention provides an apparatus for protecting private information, as shown in fig. 6, where the apparatus includes:
the intercepting unit 61 is used for intercepting the calling request information; the calling request information is calling request information sent by a third-party application program to a system camera program in the terminal equipment; the calling request information comprises a first preset address, and the first preset address is an address corresponding to the system camera program;
a first obtaining unit 62, configured to obtain a first preset address in the call request information;
a modifying unit 63, configured to modify the first preset address acquired by the first acquiring unit 62 into a second preset address; the second preset address is an address corresponding to a security camera program in the client;
and the storage unit 64 is configured to, in response to a storage instruction sent by the third-party application program, store the privacy information, which is shot by the third-party application program based on the security camera program, in the security album corresponding to the security camera program, so that the terminal device user can access the security album through the client.
Further, as shown in fig. 7, the apparatus further includes:
an adding unit 65, configured to add the secure camera program before the modifying unit 63 modifies the first preset address into a second preset address, where the secure camera program includes a photographing service and a video service;
a creating unit 66 configured to create the secure album corresponding to the secure camera program added by the adding unit 65;
a configuration unit 67, configured to configure the security camera program added by the adding unit 65 and the security album created by the dormitory creating unit 66 according to configuration information issued by the console; wherein the configuration information includes a hidden/displayed secure camera program and a secure album.
Further, as shown in fig. 7, the apparatus further includes:
and the recording unit 68 is used for recording the photographing service/video service of the security camera set by the user of the terminal equipment, and when the security camera program is called next time, the recorded photographing service/video service is used by default.
Further, as shown in fig. 7, the apparatus further includes:
a monitoring unit 69, configured to monitor the system camera program through a preset component before the intercepting unit 61 intercepts the call request information, and determine whether the call request information sent to the system camera program exists;
the intercepting unit 61 is further configured to intercept the call request information sent to the system camera program when the monitoring unit 69 monitors that the call request information exists.
Further, as shown in fig. 7, the apparatus further includes:
an encrypting unit 610, configured to encrypt the privacy information captured by the secure camera program before the storage unit 64 stores the privacy information captured by the third-party application program based on the secure camera program in a secure album corresponding to the secure camera program.
Further, as shown in fig. 7, the apparatus further includes:
a second obtaining unit 611, configured to obtain, from the secure album, the privacy information encrypted by the encrypting unit 610 when a terminal device user shares the privacy information with another terminal device user;
a sending unit 612, configured to send the privacy information obtained by the second obtaining unit 611 to other terminal device users;
an authenticating unit 613, configured to authenticate access rights of other terminal device users after the private information is sent to the other terminal device users by the sending unit 612;
the sending unit 612 is further configured to send the encrypted key corresponding to the privacy information to the other terminal device user when the authentication unit 613 succeeds in authentication.
Further, as shown in fig. 7, the apparatus further includes:
a classifying unit 614, configured to, after the storage unit 64 stores the privacy information captured by the third-party application based on the security camera program in a security album corresponding to the security camera program, classify the stored privacy information in the security album.
Further, as shown in fig. 7, the apparatus further includes:
an operation unit 615, configured to operate the privacy information in the secure album in response to an operation instruction; wherein the operation instruction comprises any of the following contents: zooming in or out of the private information, deleting the private information, sending the private information, rotating the private information, renaming the private information, clipping the private information.
According to the privacy information protection device provided by the embodiment of the invention, a client installed in a terminal device intercepts call request information, wherein the call request information is the call request information sent by a third-party application program to a system camera program in the terminal device, the call request information comprises a first preset address, and the first preset address is an address corresponding to the system camera program; secondly, the client side obtains a first preset address in the calling request information, modifies the first preset address into a second preset address, the second preset address is an address of a safe camera program in the client side for drinking, responds to a storage instruction sent by a third-party application program, and stores privacy information shot by the third-party application program based on the safe camera program into a safe photo album corresponding to the safe camera program, so that a terminal device user can access and check the privacy information in the safe photo album through the client side; compared with the prior art that huge potential safety hazards exist in photos or videos stored in an album, the third-party application program in the embodiment of the invention shoots privacy information through the safety camera in the client, executes the storage instruction sent by the third-party application program, and stores the privacy information in the safety album in the client instead of the system album of the terminal equipment, thereby ensuring the safety of the privacy information in the terminal equipment. The embodiment of the invention discloses:
a1, a method for protecting private information, comprising:
the client intercepts the calling request information; the calling request information is calling request information sent by a third-party application program to a system camera program in the terminal equipment; the calling request information comprises a first preset address, and the first preset address is an address corresponding to the system camera program;
acquiring a first preset address in the calling request information, and modifying the first preset address into a second preset address; the second preset address is an address corresponding to a security camera program in the client;
and responding to a storage instruction sent by the third-party application program, and storing privacy information shot by the third-party application program based on the security camera program into a security photo album corresponding to the security camera program, so that the terminal equipment user can access the security photo album through the client.
A2, before modifying the first preset address to a second preset address according to the method of A1, the method further comprising:
adding the safety camera program, wherein the safety camera program comprises a photographing service and a video service;
creating the secure photo album corresponding to the secure camera program;
configuring the security camera program and the security album according to configuration information issued by a console; wherein the configuration information includes a hidden/displayed secure camera program and a secure album.
A3, the method of A2, the method further comprising:
recording the photographing service/video service of the security camera set by a terminal device user so as to use the recorded photographing service/video service by default when the security camera program is called next time.
A4, according to the method in A1, before the client intercepts the call request information, the method further includes:
monitoring the system camera program through a preset component, and determining whether the calling request information sent to the system camera program exists or not;
the step of intercepting the call request information by the client comprises the following steps:
and if the calling request information sent to the system camera program exists, intercepting the calling request information.
A5, before storing the third-party application in a secure album corresponding to the secure camera program based on the privacy information captured by the secure camera program according to the method of any one of A1-A4, the method further comprising:
and encrypting the privacy information shot by the safety camera program.
A6, the method of A5, the method further comprising:
when a terminal device user shares the privacy information with other terminal device users, acquiring the encrypted privacy information from the security album, and sending the privacy information to other terminal device users;
authenticating the access authority of the other terminal equipment users;
and if the authentication is successful, sending the encrypted secret key corresponding to the private information to the other terminal equipment users.
A7, according to the method in A5, after storing the privacy information captured by the third-party application program based on the secure camera program in the secure album corresponding to the secure camera program, the method further includes:
classifying the stored privacy information within the secure album.
A8, the method of A7, the method further comprising:
responding to the operation instruction, and operating the privacy information in the secure album; wherein the operation instruction comprises any of the following contents: zooming in or out of the private information, deleting the private information, sending the private information, rotating the private information, renaming the private information, clipping the private information.
B9, an apparatus for protecting private information, comprising:
the intercepting unit is used for intercepting the calling request information; the calling request information is calling request information sent by a third-party application program to a system camera program in the terminal equipment; the calling request information comprises a first preset address, and the first preset address is an address corresponding to the system camera program;
the first obtaining unit is used for obtaining a first preset address in the calling request information;
the modifying unit is used for modifying the first preset address acquired by the first acquiring unit into a second preset address; the second preset address is an address corresponding to a security camera program in the client;
and the storage unit is used for responding to a storage instruction sent by the third-party application program, and storing the privacy information shot by the third-party application program based on the security camera program into the security photo album corresponding to the security camera program, so that the terminal equipment user can access the security photo album through the client.
B10, the apparatus of B9, the apparatus further comprising:
the adding unit is used for adding the safety camera program before the modifying unit modifies the first preset address into a second preset address, and the safety camera program comprises a photographing service and a video service;
a creating unit configured to create the secure album corresponding to the secure camera program added by the adding unit;
the configuration unit is used for configuring the security camera program added by the adding unit and the security album created by the dormitory creating unit according to configuration information issued by a control console; wherein the configuration information includes a hidden/displayed secure camera program and a secure album.
B11, the apparatus of B10, the apparatus further comprising:
and the recording unit is used for recording the photographing service/video service of the security camera set by the terminal equipment user so as to use the recorded photographing service/video service by default when the security camera program is called next time.
B12, the apparatus of B9, the apparatus further comprising:
the monitoring unit is used for monitoring the system camera program through a preset component before the interception unit intercepts the calling request information, and determining whether the calling request information sent to the system camera program exists or not;
the intercepting unit is further configured to intercept the call request information sent to the system camera program when the monitoring unit monitors that the call request information exists.
B13, the apparatus according to any one of B9-B12, further comprising:
and the encryption unit is used for encrypting the privacy information shot by the safe camera program before the storage unit stores the privacy information shot by the third-party application program based on the safe camera program in the safe photo album corresponding to the safe camera program.
B14, the apparatus of B13, the apparatus further comprising:
the second obtaining unit is used for obtaining the privacy information encrypted by the encryption unit from the security album when a terminal device user shares the privacy information with other terminal device users;
the sending unit is used for sending the privacy information acquired by the second acquiring unit to other terminal equipment users;
the authentication unit is used for authenticating the access authority of other terminal equipment users after the privacy information is sent to the other terminal equipment users by the sending unit;
and the sending unit is further configured to send the encrypted secret key corresponding to the privacy information to the other terminal device users when the authentication of the authentication unit is successful.
B15, the apparatus of B13, the apparatus further comprising:
and the classifying unit is used for classifying the stored privacy information in the security photo album after the storage unit stores the privacy information shot by the third-party application program based on the security camera program in the security photo album corresponding to the security camera program.
B16, the apparatus of B15, the apparatus further comprising:
the operation unit is used for responding to the operation instruction and operating the privacy information in the safe photo album; wherein the operation instruction comprises any of the following contents: zooming in or out of the private information, deleting the private information, sending the private information, rotating the private information, renaming the private information, clipping the private information.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
It will be appreciated that the relevant features of the method and apparatus described above are referred to one another. In addition, "first", "second", and the like in the above embodiments are for distinguishing the embodiments, and do not represent merits of the embodiments.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
The algorithms and displays presented herein are not inherently related to any particular computer, virtual machine, or other apparatus. Various general purpose systems may also be used with the teachings herein. The required structure for constructing such a system will be apparent from the description above. Moreover, the present invention is not directed to any particular programming language. It is appreciated that a variety of programming languages may be used to implement the teachings of the present invention as described herein, and any descriptions of specific languages are provided above to disclose the best mode of the invention.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.
Those skilled in the art will appreciate that the modules in the device in an embodiment may be adaptively changed and disposed in one or more devices different from the embodiment. The modules or units or components of the embodiments may be combined into one module or unit or component, and furthermore they may be divided into a plurality of sub-modules or sub-units or sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.
The various component embodiments of the invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functionality of some or all of the components in the title of the invention (e.g., means for determining the level of links within a web site) in accordance with embodiments of the invention. The present invention may also be embodied as apparatus or device programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present invention may be stored on computer-readable media or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.