Cryptanalysis and Improvement of an RSA Based Remote User Authentication Scheme Using Smart Card

User’s password with smart card based authentication protocol is needed to access resources securely from remote server. In 2014, Huang et al. proposed a timestamp-based authentication protocol and they claimed that their scheme is secure against all possible attacks. In this paper, we have pointed out that Huang et al.’s scheme is insecure against off-line password guessing attack, insider attack and forgery attack. Beside these, inefficient password update phase can lead to denial of service. To remove these security loopholes, we have proposed an efficient RSA-cryptosystem based remote user authentication scheme using smart card. Security (formal and informal) analysis shows that the proposed scheme provides better security tradeoff than Huang et al.’s scheme. Further, we have simulated our proposed scheme for the formal security verification using Automated Validation of Internet Security Protocols and Applications tool to confirm that the proposed scheme is secure against passive and active attacks. Performance analysis shows that the proposed scheme provides lower computational and communication cost than Huang et al.’s scheme as well as other related competitive existing schemes.