The Diffie-Hellman Key Exchange scheme can produce a common session key between the two communicators, but its problem is that it makes a man-in-the middle attack possible. To solve problems like these, several protocols have been put forward, and the...
The Diffie-Hellman Key Exchange scheme can produce a common session key between the two communicators, but its problem is that it makes a man-in-the middle attack possible. To solve problems like these, several protocols have been put forward, and the Simple Authenticated Key Agreement (SAKA) Protocol is among them. Seo-Sweeney suggested a SAKA protocol initially and the protocol has weakness that a malicious 3rd party can masquerade a valid user. Tseng suggested another protocol that advances this problem but this protocol can still be attacked when the messages in key verification phase are identical. Ku-Wang suggested a new protocol that advances this problem. Kim-Kim-Hwang also suggested a new SAKA protocol and confirmed that their protocol has same safeness and better performance compared to the other SAKA protocols. In this paper, we reanalyze the safeness of SAKA protocols and find out that Kim-Kim-Hwang protocol has not only better performance but also better safeness.