Security enhancement for the "simple authentication key agreement algorithm"

The weaknesses of the simple authenticated key agreement (SAKA) protocol were shown by H. Sun (2000). These weaknesses include the following facts: (1) it cannot detect a masquerade, (2) it cannot withstand a dictionary attack, and (3) it cannot provide perfect forward secrecy. In this paper, we improve the SAKA algorithm to overcome these weaknesses. In addition, we show that the improved scheme is more simple and more secure than the original one.