Formal Treatment of Privacy-Enhancing Credential Systems

Privacy-enhancing attribute-based credentials (PABCs) are the core ingredient to privacy-friendly authentication systems, allowing users to obtain credentials on attributes and prove possession of these credentials in an unlinkable fashion while revealing only a subset of the attributes. To be useful in practice, however, PABCs typically need additional features such as i) revocation, ii) pooling prevention by binding credentials to users secret keys, iii) pseudonyms as privacy-friendly user public keys, iv) proving equality of attributes without revealing their values, v) or advanced issuance where attributes can be blindly carried over into new credentials. Provably secure solutions exist for most of these features in isolation, but it is unclear how they can be securely combined into a full-fledged PABC system, or even which properties such a system would aim to fulfill. We provide a formal treatment of PABC systems supporting the mentioned features by defining their syntax and s...

• Type: Journal
• Year: 2015
• Where: SACRYPT
• Authors: Jan Camenisch, Stephan Krenn, Anja Lehmann, Gert Læssøe Mikkelsen, Gregory Neven, Michael Østergaard Pedersen
• Keywords: Cryptology, SACRYPT 2015