Xie and Yu (2005) proposed a group signature scheme and claimed that it is the most efficient group signature scheme so far and secure. In this paper, we show that two dishonest group members can collude to launch two attacks on the scheme. In the first attack they can derive the group secret key and then generate untraceable group signatures. In the second attack, they can impersonate other group members once they see their signatures. Therefore we conclude that the signature scheme is not secure. We show that some parameters should be carefully selected in the scheme to resist our attacks.
展开▼
机译：Xie and Yu（2005）提出了一种组签名方案，并声称它是迄今为止最安全的最有效的组签名方案。在本文中，我们显示了两个不诚实的小组成员可以合谋发起对该方案的两次攻击。在第一次攻击中，他们可以派生组密钥，然后生成不可追踪的组签名。在第二次攻击中，一旦看到他们的签名，他们就可以冒充其他小组成员。因此，我们得出结论，签名方案是不安全的。我们表明，应在方案中谨慎选择一些参数以抵抗我们的攻击。
展开▼
