对新鲜性进行了细粒度的定义,并将新鲜性和秘密性结合,完善了基于新鲜性原则的密码协议分析方法。区分了不同主体产生的新鲜性标识符的可信任新鲜性,并对私有秘密和共享秘密给予了更准确的解释。改进后的基于新鲜性原则的密码协议分析方法能够分析并发现Helsinki协议中存在的微妙的安全缺陷。
Fine-grained definitions of freshness are presented,and both freshness and secrecy are combined to improve the security analysis of cryptographic protocols.Trusted freshness of the nonces generated by different principals are explicitly distinguished.More exact explanations on the private secrecy and shared secrecy are given.The improved method can analyze and find out some existing subtle weaknesses in the Helsinki protocol.