Off-line password-guessing attacks on the generalized key agreement and password authentication protocol

In this paper, we show that the generalized key agreement and password authentication protocol, proposed by Kwon and Song [T. Kwon, J. Song, A study on the generalized key agreement and password authentication protocol, IEICE Trans. Comm. E83-E (9) (2000) 2044-2050], is vulnerable to off-line password guessing attacks.