Anonymous trace and revoke

A broadcast encryption (BE) scheme is a method for encrypting messages in a way that only a set of privileged users can decrypt it. Anonymity in a BE system is to hide any information on the privileged set. This problem has very recently had some attention and some constructions are proposed to achieve anonymity. However, anonymity in a trace and revoke (TR) scheme has not been studied yet, and to the best of our knowledge there is no construction for an anonymous TR system. In this paper, we present a generic transformation from an anonymous BE scheme into an anonymous TR scheme.