Cryptanalysis of an Efficient Passwortd Authentication Scheme.

Abstract

Password authentication schemes are one of the most commonly used solution to protect resources in network environment from unauthorized access. Since, their first introduction in [9], many password authentications schemes have been proposed and analysed by crypto com- munity. Contribution of the present paper is two-folded. At first it presents the cryptanalysis results of Ramasamy et al.'s RSA based password authentication scheme [11] and shows that it is vulnerable to privileged insider at- tack, password guessing attack and Impersonation attack. Secondly, modifications to the scheme were suggested to overcome the vulnerabilities. Formal security analysis of the proposed scheme was presented using BAN logic. In addition to being secure the modified scheme facilitate password update and mutual authentication. Efficiency comparison of the modified scheme is presented.