对可撤销匿名性的盲代理签名方案的注记

对王晓明、符方伟所设计的一类可撤销匿名性的盲代理签名方案进行密码学分析，发现该方案效率不高，数据冗余量大，方案中的代理签名人具有滥用代理签名密钥进行代理签名的能力，并且能够对自己所生成的有效代理签名进行事后否认，即不满足代理签名权力的不可滥用性及代理签名的不可否认性两个基本性质，同时该方案并非作者所宣称的那样是不可伪造的，文章最后给出了一个对代理签名的伪造攻击，并针对该攻击提出了改进方法．

Remarks on an Anonymity-Revoking Blind Proxy Signature Scheme

It is found that the anonymity-revocable proxy signature scheme proposed by Wang Xiao-Ming and Fu Fang-Wei is in fact, not unforgeable, as claimed. There are redundancy steps and infeasible operations in the scheme, thus the efficiency of the scheme is low. Also the proxy signer can repudiate a valid proxy signature generated by himself before and may use the proxy key pair to generate any proxy signatures freely that unauthorized by the original signer. Therefore, the scheme does not satisfy the properties of undeniable and misuse of the proxy key. Finally, after detailed cryptanalysis a forgery-attack is proposed and possible improvement is discussed.