在标准模型下安全的基于身份的代理签名方案

代理签名允许原始签名人把他的签名权委托给代理签名人, 这样代理签名人能够代表原始签名人对消息进行签名. 代理签名可以应用到许多领域, 例如分布式系统, 网格计算和移动代理等. 将代理签名与基于身份的密码学结合起来, 人们提出了一些基于身份的代理签名方案, 可是它们的安全性证明都是在随机预言模型下获得的, 这样它们在现实环境中不一定是安全的. 利用Paterson等的基于身份的签名方案构造了一个基于身份的代理签名方案, 并在标准模型下基于计算Diffie-Hellman假设证明了它的安全性.

Identity-based Proxy Signature Schemes Secure in the Standard Model

A proxy signature enables an original signer to delegate her signing capability to a proxy signer and then the proxy signer can sign messages on behalf of the original signer. Proxy signatures have found numerous practical applications, particularly in distributed systems, Grid computing, and mobile agent, etc. Combining proxy signature with identity based cryptography, some identity-based proxy signature schemes have been proposed in the past years. However, the security of these schemes is proven in the random oracle model which does not imply security in the real world. In this paper, the first identity-based proxy signature scheme without random oracles is proposed based on Paterson, et al’s identity-based signature scheme. The unforgeability of the proposed scheme is based on the hardness of the well known computational Diffie-Hellman problem.