Efficient Two-Factor Authentication Protocol Using Password and Smart Card

Two-factor authentication using password and smart card could reduce the risk than the use of a password alone. Recently, Chen et al. proposed a two-factor remote user authentication protocol using password and smart card and provide the criteria of authentication protocols. They claimed their protocol is secure against certain known attacks. In this paper, the authors showed that Chen et al.'s scheme is still vulnerable to the off-line password guessing attack, privileged administrator attack, key control attack and lacks of forward security. To solve these security problems, we propose an efficient two-factor authentication and key agreement protocol..