Implementing Group Signature Schemes With Smart Cards

Group signature schemes allow a group member to sign messages on behalf of the group. Such signatures must be anonymous and unlinkable but, whenever needed, a designated group manager can reveal the identity of the signer. During the last decade group signatures have been playing an important role in cryptographic research; many solutions have been proposed and some of them are quite efficient, with constant size of signatures and keys ([1], [6], [7] and [15]). However, some problems still remain among which the large number of computations during the signature protocol and the difficulty to achieve coalition-resistance and to deal with member revocation. In this paper we investigate the use of a tamper-resistant device (typically a smart card) to efficiently solve those problems.