基于用户身份加密体系中的门限代理签密方案

基于用户身份的加密体系是一种新型的公钥加密体系,在这种体系中,用户的身份标志或是从身份标志中衍化出来的字符串序列就是他们的公钥。在一个门限值为(t,n)的代理签名方案中,源签名人可以把他(或她)的签名权利委派给n个代理签名人,从而使得任何大于等于t个代理签名人可以代表源签名人对信息进行签名,而小于等于(t-1)个代理者却没有这种权利。然而,在许多情况下人们希望一个方案能同时满足保密性、可认证性以及不可否认性。文章提出了一种在双线性对偶映射下的基于用户身份加密体系中的门限代理签密方案,并且分析了该方案的安全性。

Identity Based Threshold Proxy Signcryption Scheme

An identity based cryptosystem is a novel type of public cryptographic scheme in which the public keys of the users are their identities or strings derived from their identities.In a (t,n) proxy signature scheme,the original signer can delegate his/her signing capability to n proxy signers such that any t or more proxy signers can sign messages on behalf of the former,but t-1 or less of them cannot do the same thing.However,in many situations we want to enjoy confidentiality,authenticity and non-repudiation of message simultaneously.In this paper we propose an identity based threshold proxy signcryption scheme using bilinear pairings.The security of the scheme is also analyzed.