基于辫群的代理签名方案的分析与改进

对两个基于辫群的代理签名方案进行了分析，发现它们并不满足不可伪造性。第一个方案中不能抵抗原始签名人改变攻击，在第二个方案中任何攻击者可以伪造一个有效的代理签名，在该签名中，代理签名者以及消息可以任意指定。根据上述缺陷，提出一个改进的强代理签名方案， 新方案在不增加计算复杂性的前提下，保证了签名的安全性，同时代理授权过程中还增加了不需要安全通道的性质。

Analysis and improvement of proxy signature schemes over braid group

Analysis shows that two proxy signature schemes based on braid groups are insecure:the first scheme cannot resist the original signer's change attack;in the scheme of second,any antagonist can successfully forge a valid proxy signature scheme,which the antagonist can designate any proxy signer and messages.Later,a new proxy signature scheme was proposed.Analysis shows that the proposed scheme satisfies all security requirements;what's more,no security channel is in need in the communication of the original ...