Security Pitfalls of an efficient remote user authentication scheme using smart cards

In 2004, W. C. Ku and S. M. Chen proposed an efficient remote user authentication scheme using smart cards to solve the security problems of Chien et al.’s scheme. Recently, Hsu and Yoon et al. pointed out the security weakness of the Ku and Chen’s scheme Furthermore, Yoon et al.’s scheme also proposed a new efficient remote user authentication scheme using smart cards. This paper analyzes the security pitfalls of Yoon et al’s scheme and aims to show that the Yoon et al.’s scheme is still vulnerable to the password guessing attack and the insider attack. Index Terms — Cryptography, Authentication, Smart cards, Password, Check digit.