Lee-Chang的指定验证者签名方案的安全分析

Cryptanalysis of Lee-Chang Designated Verifier Signature Scheme

为解决普通签名的可否认性问题,Lee和Chang提出了无Hash函数的强指定验证者签名,并在此基础上提出了强指定验证者环签名方案。本文首先证明该强指定验证者签名方案是存在性可伪造,接着指出强指定验证者环签名方案虽然安全但计算低效,最后在保证不改变安全条件的情况下,改进了强指定验证者环签名方案。实践表明,该改进方案不可伪造而且更加高效。

To obtain the deniable property,Lee and Chang proposed a strong designated verifier signature scheme without hash functions,and also constructed a strong designated verifier ring signature scheme.In this paper,first,it is pointed out that forgery still exists for the strong designated verifier signature scheme,then,although the strong designated verifier ring signature scheme is safe,yet it is inefficient.Last,an improved strong designated verifier ring signature scheme is proposed with the safety conditions unchanged.Cases study show that counterfeit is prevented by using the improved scheme and more efficiency is attained.