标准模型下基于身份的动态门限代理签名方案

目前对于基于身份的门限代理签名方案来说，方案的安全性大多是在随机预言模型下证明的，并且这些门限代理签名方案中的代理签名密钥固定。相对而言，设计标准模型下的动态门限代理签名方案更有实际意义。针对以上两个问题，根据Paterson提出的基于身份的签名方案，利用计算Diffi}Hellman问题的困难性在标准模型下设计了一个代理签名密钥可变的动态门限代理签名方案。最后，利用双线性对技术对方案的正确性进行了严格证明，并在CDH困难假设下给出了方案安全性的详细分析过程和证明，结果表明方案是可证安全的和可靠的。

ID-based Proactive Threshold Proxy Signature in the Standard Model

At present, the security of the identity based proactive threshold proxy signature schemes was almost proven in the random oracle model, and the threshold value of these schemes was almost changeless. It is more practical to design threshold proxy signature scheme in the standard model, compared with the existing ones. Aiming at the two problems pointed out above, this paper presented a proactive threshold proxy signature scheme by using the hardness of the computational DifficHellman problem with changeable threshold value, based on the modification of Paterson' proposed identity based signature scheme. At last, the scheme's correctness was exactly proven in terms of bilinear pairing technique and its security analysis and prove were given in detail in the assumption of the computational Diffie-Hellman problem, therefore, this scheme was proven secure and reliable.