Abstract: The security of the LiZhang's IDbased proxy blind signature scheme from bilinear pairings was analyzed, and it was found that this scheme did not possess the unforgeability property. The original signer can forge a valid proxy blind signature for any message, and the proxy signer can misuse the signing capabilities. At the same time, the proxy signer can make a linkage between a signature and the corresponding message of signing protocol after signing, which is called linkability. An improved proxy blind signature scheme was proposed, which can resolve the security problems existing in the original scheme and satisfy other required properties of a proxy blind signature scheme. The calculative complexity is lower than that of the other schemes despite a little increase.

Key words: identity-based, proxy blind signature, unlinkability, forgery attack

摘要： 通过对 Li-Zhang 基于双线性映射的基于身份的代理盲签名方案的分析，指出该方案并不满足不可伪造性，原始签名人可以伪造一个有效的代理盲签名，代理签名人可以滥用代理签名权，同时当签名被用户泄露后，代理签名人能将自己在签名协议中的签名和签名的消息联系起来，这就是所谓的可追踪性。在此基础上提出了改进的代理盲签名方案，改进后的方案有效克服了原方案的安全缺陷，并满足代理盲签名所需要的各种安全性要求，其计算量虽有少量增加，但仍低于其他同类方案。

关键词: 基于身份, 代理盲签名, 不可追踪性, 伪造攻击