Security Analysis of A Dynamic ID-based Remote User Authentication Scheme

Since 1981, when Lamport introduced the remote user authentication scheme using table, a plenty of schemes had been proposed with table and without table using. Recently Das, Saxena and Gulati have proposed A dynamic ID-based remote user authentication scheme. They claimed that their scheme is secure against ID-theft, and can resist the reply attacks, forgery attacks, and insider attacks and so on. In this paper we show that Das et al.’s scheme is completely insecure and using of this scheme is equivalent to an open server access without any password. 1 Index Terms — Authentication, cryptography, security, cryptanalysis, smart cards, proxy user.