对一个基于离散对数代理盲签名的密码分析

顾名思义,代理签名让原始签名者可以将其数字签名权力委托给代理签名者,使其能够代理原始签名者签发指定的数字消息;盲签名使用户能将给定的消息让别人签发,而又不泄漏任何有关的信息给签名者.在Schorr盲签名的基础上,谭作文等结合代理签名和盲签名提出了一个基于离散对数的代理盲签名方案.研究表明该方案是不安全的.它既受到广泛伪造攻击,又是可连接的.我们还进一步说明,原文安全性定理的证明是不正确的.

Cryptananlysis of a Proxy Blind Signature Scheme Based on DLP

Proxy signature allows an original signer to delegate his/her signing capability to a proxy signer such that the proxy signer can sign messages on behalf of the original signer. Blind signature allows a user to have a given message signed by the signer without revealing any information about the message. By using Schnorr blind signature, Tan et al. recently proposed a digital proxy blind signature scheme. They claimed that it satisfies the security properties of both blind signatures and proxy signatures. However, it is not the fact. This paper shows that the proposed scheme is vulnerable to universal forgery as well as linkability attacks. It also explains why their proofs of the security are incorrect.