对两种代理盲签名体制的密码学分析

代理盲签名结合了代理签名与盲签名的优点，而多级代理签名实现了签名权利在许可范围内逐级向下代理的要求。利用椭圆曲线上的双线性对，陈玲玲等人提出了一种基于身份的代理盲签名方案，胡江红等人提出了一种基于身份的多级强代理盲签名方案。给出了这两个方案的密码学分析，指出在陈玲玲等人的方案中，代理签名人可以利用授权证书计算得到原始签名人的私钥，从而可直接伪造原始签名人的签名或授权，同时指出所提的两个方案也无法满足不可追踪性．代理签名人可以将自己在签名协议中的签名和签名的消息联系起来从而跟踪消息的拥有者，从而证明了这两个方案是不安全的。

Cryptanalysis of Two Proxy Blind Signature Schemes

The proxy blind signature scheme combines the good properties of both proxy signature and blind signature scheme, while the multi-level proxy signature scheme can realize step by step under .agreement. Recently, based on bi- linear pairings of elliptic curve, Chen Lingling proposed an ID-based proxy blind signature scheme, and Hu Jianghong proposed an ID-based multi-level proxy blind signature scheme. Through the cryptanalysis of the two schemes, it shows that in Chen＇ s scheme, the proxy signer can calculate the original signer＇ s private key by receiving his authorization, and then he can forge any signature or authorization direcdy. At the same time, the two proposed schemes can not satis- fy the untraceability, the proxy signer can link a signature to the corresponding message of signing protocol so that he can trace the message holder, therefore the two schemes are not secure.