目前已经提出的代理签名方案缺乏在完整的代理签名安全模型下证明方案的安全性.在Boldyreva等人提出的代理签名安全模型的基础上,对代理签名的可证安全模型进行详细的形式化定义,提出一种完整的代理签名可证安全模型.同时,为了展示该安全模型的有效性和可扩展性,对Paterson等人提出的标准模型下基于身份的签名方案进行扩展,提出在标准模型下基于身份的代理签名方案,并在可证安全模型下,证明新方案具有在自适应选择消息攻击下存在基于身份的代理签名不可伪造性,其安全性在标准模型下可归约于CDH问题假定.新方案与标准模型下基于公钥密码体制的代理签名方案相比,不仅增加了用户身份的概念,还具有更完备的安全性.%Current proxy signature schemes are not proved for their security in the complete provable security model of proxy signature. In this paper, we show a complete provable security model for proxy signature based on Boldyreva's provable security model, and a new identity-based proxy signature scheme are proposed in the standard model, which is based on Paterson's scheme. In the complete provable security model for proxy signature, the new scheme is proved to have the existential identity-based proxy signature unforgerability under an adaptive chosen message attack, which has a security reduction to CDHP. Comparing with other proxy signature schemes based on public key cryptosystem in the standard model, the concept of the identity is introduced into the new scheme, and the new scheme is more secure.
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