基于身份的认证密钥协商协议的安全分析与改进

Analysis and improvement of an ID-based authenticated key agreement protocol

对基于身份的标准模型下可证明安全的认证密钥协商协议进行安全性分析,发现恶意的密钥生成中心(PKG,private key generator)能计算出所有的会话密钥,即它在无会话密钥托管模式下不满足PKG前向安全性。因此,为满足无托管的要求,提出一个改进的基于身份的认证密钥协商协议,并在标准模型下证明其为安全的认证密钥协商协议。结果表明,改进后协议满足完善前向安全性和PKG前向安全性。

The security of a recently proposed ID-based authenticated key agreement protocol was analyzed. Although it is provably secure in the standard model, a malicious PKG （private key generator） can still obtain all of the agreed session keys, that is, it doesn＇t provide PKG-forward secrecy in escrowless mode. To satisfy the security requirement in escrowless mode, an improved version of the protocol was presented and it was proved to be a secure authenticated key agreement in the standard model. Results show that it provides perfect forward secrecy and PKG-forward secrecy.