一种动态门限群签名方案的安全性分析

Cryptanalysis of a Dynamic Threshold Group Signature Scheme

门限群签名是群签名的推广,其中只有授权子集才能代表整个群体进行签名。一旦发生纠纷,签名成员的身份可以被追查出来。指出一种动态门限群签名方案有冗余,提出了针对该签名三种攻击。分析结果证明该门限群签名方案不具有防冒充性,不能抵抗合谋攻击,门限的动态更新、群成员注销和系统密钥更新也不安全。

The threshold group signature is a generalization of group signature, in which only authorized subset can represent the group to generate signature and the identifies of signers of a signature can be opened in case of later dispute. We point out the redundancy of a dynamic threshold group sigtature scheme and demonstrate three attacks on it. The security analysis indicates that the scheme is not secure against framing attack and cannot resist conspiratorial attack and the threshold value cannot be renewed safely.