Achieving Optimal Anonymity in Transferable E-Cash with a Judge

Oliver Blazy, S??bastien Canard, Georg Fuchsbauer, Aline Gouget, Herv?? Sibert, Jacques Traor??, Achieving Optimal Anonymity in Transferable E-Cash with a Judge. Progress in Cryptology - AFRICACRYPT 2011. ISBN 978-3-642-21968-9, pp. 206–223. July 2011. No electronic version available. External information


Electronic cash (e-cash) refers to money exchanged electronically. The main features of traditional cash are usually considered desirable also in the context of e-cash. One such property is off-line transferability, meaning the recipient of a coin in a transaction can transfer it in a later payment transaction to a third person without contacting a central authority. Among security properties, the anonymity of the payer in such transactions has been widely studied. This paper proposes the first efficient and secure transferable e-cash scheme with the strongest achievable anonymity properties, introduced by Canard and Gouget. In particular, it should not be possible for adversaries who receive a coin to decide whether they have owned that coin before. Our proposal is based on two recent cryptographic primitives: the proof system by Groth and Sahai, whose randomizability enables strong anonymity, and the commuting signatures by Fuchsbauer, which allow one to sign values that are only given as encryptions.

Bibtex entry.

Contact details

Publication Admin