对一群签名方案的分析与改进

通过对夏祥盛等人的动态门限群签名方案的研究，指出该方案的若干不足，其中最主要的不足是通过伪造和不可追踪性，并对该方案进行了改进．与现有群签名方案不同，新方案中用户的秘密数由用户自己选取，从而避免了双线性对的计算，大大提高了效率．分析说明改进的群签名方案几乎克服了原方案的所有缺点．

Cryptanalysis and Improvements of a Group Signature Scheme

We investigate the security of a dynamic threshold group signature scheme proposed by Xia et al.,and point out several weaknesses of their scheme.The most serious weaknesses are universal forging and untraceability.We aslo improve their scheme.In our scheme,user's secret is chosen by himself.And there no bilinear pairing operations during the whole scheme,though the security of our scheme is based on elliptic curve discrete logarithm problem.Analysis shows that new scheme conquers almost all weaknesses of t...