Weaknesses and improvements of an efficient password based remote user authentication scheme using smart cards
Wei‐Chi Ku, Shuai-Min Chen · IEEE Transactions on Consumer Electronics · 2004
Recently, Chien et al. proposed an efficient remote authentication scheme using smart cards. However, we find that their scheme is vulnerable to a reflection attack and an insider attack. In addition, their scheme lacks reparability. Herein, we first show the weaknesses of Chien et al.'s scheme, and then propose an improved scheme with better security strength.