一个基于中国剩余定理的群签名方案的攻击及其改进方案

该文给出了对一个已有的群签名方案的攻击，表明了已有的群签名不能防止群成员的联合攻击，在联合攻击下攻击者可以得到任何群成员的秘钥从而伪造任何人的签名。同时该方案也不能防止不诚实的管理员伪造群成员的签名。利用Schnorr签名方案给出了一种改进方案，新的改进方案具有以下特点:联合攻击下是安全的；可以防止不诚实的群中心伪造群成员的签名；可以简单高效地实现成员撤消。

An Attack and Improve of a Group Signature Scheme Based on Chinese Remainder Theorem

An attack is mounted on a group signature scheme based on Chinese Remainder Theory(Chen-Scheme). It shows the Chen-Scheme is insecure: A colluding subset of group members can find the private key of other members and forge their signatures; The dishonest group center can produce a valid signature on behalf of group members. Using Schnorr signature scheme this paper proposes an improve scheme, which has good characteristics: A colluding subset of group members can not produce a valid signature that the group manager can not open; A dishonest group center can not sign messages on behalf of other members; The revocation of the membership is efficient .