Anonymous Single Sign-On With Proxy Re-Verification

摘要

An anonymous single sign-on (ASSO) scheme allows users to access multiple services anonymously using one credential. We propose a new ASSO scheme, where users can access services anonymously through the use of anonymous credentials and unlinkably through the provision of designated verifiers. Notably, verifiers cannot link a user's service requests even if they collude. The novelty is that when a designated verifier is unavailable, a central authority can authorize new verifiers to authenticate the user on behalf of the original verifier. Furthermore, a central verifier can also be authorized to de-anonymize users and trace their service requests. We formalize the scheme along with a security proof and provide an empirical evaluation of its performance. This scheme can be applied to smart ticketing where minimizing the collection of personal information of users is increasingly important to transport organizations due to privacy regulations such as general data protection regulations (GDPRs).