ACJT群签名方案中成员撤消的高效实现

成员撤消问题是设计群签名方案中的一个难题,到目前为止尚无满意的解决办法.在ACJT群签名方案的基础上,提出了新的成员撤消方法.在新方案中,管理员在撤消一个成员时仅需要一次乘法运算来更新群公钥,签名和验证算法的计算量均独立于目前群成员个数和被撤消的成员个数,因而算法是高效的.以前的具有撤消成员功能的群签名方案,签名和验证算法的计算量要么依赖当前的群成员个数,要么依赖被撤消的群成员个数,而且群公钥的更新或者成员密钥的更新往往需要多次指数运算.

An Efficient Revocation Algorithm in ACJT Group Signature

The problem of secure and efficient revocation of membership without incurring big costs has been considered, but no satisfactory solution was reported. This paper proposes a new revocation method of membership based on the ACJT group scheme. The solution is efficient in that it only needs one multiplication to update the public key for the group manager to exclude one group member, and the signing and verifying procedure is independent of the number of the current and excluded group members. To the best of our knowledge, the signing and verifying procedure in the existing revocation schemes is dependent on the number of either the current or the excluded group members, and thus the group manager needs a heavy computation load to update the public key.