Cryptanalysis of recently proposed Remote User Authentication Schemes

Recently Manik et al. [13] proposed a novel remote user authentication scheme using bilinear pairings. Chou et al. [14] identified a weakness in Manik et al.’s scheme and made an improvement. In this paper, we show that both Manik et al.’s and Chou et al.’s schemes are insecure against forgery attack and replay attack