Improvement on Security of a Practical Solution to Remote Authentication

Chien, Jan, and Tseng proposed a practical solution to remote authentication using smart cards in 2002. This scheme is efficient and provides mutual authentication between the user and the server. In this paper a security breach is shown to exist in Chien-Jan-Tseng scheme; an intruder can easily impersonate a legal user to login the remote server or impersonate the server to cheat the user. A nonce-based scheme is put forward to preclude these potential attacks. Also the improved solution can avoid the replay attacks of the user's login message and the server's authentication message