Fair Blind Signatures without Random Oracles

A fair blind signature is a blind signature with revocable anonymity and unlinkability, i.e. an authority can link an issuing session to the resulting signature and trace a signature to the user who requested it. In this paper we first revisit the security model for fair blind signatures given by Hufschmitt and Traore in 2007. We then give the first practical fair blind signature scheme with a security proof in the standard model. Our scheme satisfies a stronger variant of the Hufschmitt-Traore model.