对一个基于身份的多重签密方案的分析和改进

摘要

Waters提出了一个标准模型下的基于身份的加密和签名方案,Paterson和Schuldt在此基础上提出了一个基于身份的签名方案.Zhang和Xu在上述两个方案的基础上,提出了一个基于身份的多重签密方案.本文指出Zhang-Xu的方案会受到私钥随机化攻击,并在标准模型下提出了一个改进的基于身份的多重签密方案,其中将解密私钥和签名私钥分开,用于签名的私钥无法随机化,同时该方案还可以抵抗内部泄漏攻击.%Waters proposed an identity-based encryption and signature scheme in standard model.Then Paterson and Schuldt proposed an identity-based signature scheme based on Waters' IBE. Zhang and Xu proposed an identity-based multi-signcryption scheme that using the above schemes. However, we show that Zhang-Xu's scheme is insecure under randomizing private key attack. Furthermore, we propose an improved identity-based multi-signcryption scheme in standard model. In our scheme, we divide the private keys into two parts,one is for decryption, the other is for signature, and the private key used for signature cannot be randomized. Moreover, our scheme can resist insider leak attack.