| Abstract: | Abstract In 2006, Shieh et al. proposed an efficient remote mutual authentication and key agreement scheme which uses smart cards and requires only hash function operations. In this paper, we show that Shieh et al.'s scheme is vulnerable to guessing attacks, forgery attacks and key compromise attacks. To eliminate these weaknesses, an improvement of Shieh et al.'s scheme with increased security is proposed. The security and efficiency of the improved scheme raises the attractiveness for implementation. |
