EVLA: Extended-Validation Certificates with Location Assurance

Transport Layer Security (TLS) is a de facto standard for secure communication over the Internet and other critical infrastructures. The trust model deployed in the TLS is based on digital certificates which contain signed assertions on bindings between identities and their public key. Such a certificate is issued by a trusted certification authority (CA) that verifies an identity-key binding during a certificate validation process. As different applications require different grades of security, CAs have introduced different types of certificates and validations. So-called, extended validation (EV) certificates are believed to be the most secure, as to issue such a certificate a CA has to conduct a rigorous identity verification procedure. However, it turns out that in practice such certificates may not provide any additional security, as it is challenging to check whether a CA indeed has verified an identity according to the procedure. In this paper, we consider how to add value to the security of EV certificates. We propose Extended-Validation Certificates with Location Assurance (EVLA), a blockchain-based system that increases the security of EV certificates through checking and asserting that a CA and a given entity indeed have met during the certification process. We discuss possible ways of realizing EVLA and their implications.