针对最近一些学者提出的前向安全的代理签名方案和改进的前向安全的代理签名方案,给出了这两种代理签名方案的安全性分析,并指出它们是不安全的,均不具备前向安全性质。当代理人的私钥泄露后,前向安全的代理签名方案不能抵抗伪造攻击;而改进的前向安全的代理签名方案对攻击者来说仅利用公开的信息就可以实施伪造攻击。
Recently,some researchers proposed a forward secure proxy signature scheme and an improved forward-secure proxy signature scheme.This paper analyzed the security of the two proxy signature schemes and pointed out they were insecure and had not the characteristic of forward security at all.The first scheme couldn t resist forgery attack while the secret key of the proxy signer was lost.If adversary knew some public information of the second scheme,he/she could forge proxy signature.