对一种代理盲签名方案的密码学分析

Cryptanalysis of proxy blind signature scheme

Zhao等提出了一个新的代理盲签名方案,并在此基础上,考虑了签名方程中所有可能的参数选取方法,由此给出了构造代理盲签名方案的一般方法,给出了生成代理密钥的8个方程式。对他们提出的代理盲签名进行了分析,给出了一种伪造攻击,利用这种攻击,不诚实的原始签名人可以成功伪造代理签名密钥,从而假冒诚实的代理签名人生成验证有效的签名,威胁到代理签名人的权益。在Zhao等给出的8种代理密钥方程式中,有一半都无法抵抗这种攻击。

A new proxy blind signature scheme was proposed by Zhao et al. recently. Based on this scheme, all possible parameters to be chosen in signature equations were considered and a general method to construct proxy blind signature was obtained, They also proposed eight equations to generate secure proxy signing key. However, their scheme was insecure. A forgery attack on their proxy blind signature scheme was proposed in this paper. Using the forgery attack, a dishonest original signer can forge the proxy signing key and produce valid proxy blind signatures. Among the eight equations of producing proxy signing key, half of them can not resist this kind of attack.