关键词: 签密, 密钥协商, 强安全性, 冗余, 被动攻击, 主动攻击

Abstract: Based on signcryption scheme, Liu-Xu proposes an efficient certificateless authenticated two-party key agreement protocol. Security analysis shows that the scheme hasn’t achieved strong security due to redundancy of the exchange messages. The scheme is vulnerable to passive attack and active attack. To overcome the problem mentioned above, an improved scheme without using signcryption scheme is proposed. Analysis result proves that the efficiency and security of the proposed protocol is improved.

Key words: signcryption, key agreement, strong security, redundancy, passive attack, active attack