具有快速撤销功能的代理签名方案

针对很多代理签名方案没有解决的代理撤销问题，基于双线性对，提出了一个新的代理签名方案．新方案利用(2， 2)门限思想，引入一个安全中介SEM，其作用是：(1)帮助合法的代理签名人生成有效的代理签名;(2)监督代理签名人是否按照授权证书的规定签名;(3)检查代理签名人的签名权利是否被撤销．新方案不仅满足代理签名的所有安全要求，而且代理签名人只有与SEM合作才能生成有效的签名，使得方案具有快速撤销的功能．

Proxy signature scheme with fast revocation

Many proxy signature schemes have the defect that they cannot solve the proxy revocation problem.Based on the bilinear pairings,a new proxy signature scheme is proposed in this paper.Motivated by the idea of(2,2) threshold,a security mediator(SEM) is introduced in our scheme to(1) help a proxy signer to generate valid proxy signatures,(2) examine whether a proxy signer signs according to the warrant,and(3) check the revocation of a proxy signer.It is shown that the proposed scheme satisfies all the security requirements for a secure proxy signature.Moreover,a proxy signer must cooperate with the SEM to generate a valid proxy signature,which makes the new scheme have an effective and fast proxy revocation.