一些环签名及其扩展签名方案的安全性分析及改进

Cryptanalysis and Improvements of Some Ring Signature and Its Extended Signature Schemes

通过对Zhang(2007),Li-Chen-Yuen-Wang(2006),Li-Wang(2006)和Zhu-Zhang-Wang(2009)提出的环签名及其扩展签名方案进行密码学分析,指出了这几个方案所存在的安全性缺陷,基于其安全性缺陷提出了群成员改变攻击方法或匿名性攻击方法.为避免这些缺陷,利用Herranz-Saez(2003)环签名方案的一般模式和分叉引理对原方案进行改进,改进后的方案是可证安全的.

The security flaws of the ring signature and its extended signature schemes proposed by Zhang（2007）,Li-Chen-Yuen-Wang（2006）,Li-Wang（2006） and Zhu-Zhang-Wang（2009） are analyzed.It points out that these schemes can not resist the group-changing attack or anonymity attack.The attack methods are presented based on their security flaws.In order to avoid these flaws,we make use of the generic construction method and the corresponding forking lemma of ring signature scheme from Herranz-Saez（2003） to improve the original signature schemes.The improved signature schemes are provably secure.