Further Analysis and Improvement of Yoon et al.´s Hash-Based User Authentication Scheme

In 2002, Lee et al. proposed a scheme improving on Peyravian and Zunic scheme. However, Yoon et al. found that the scheme is vulnerable to a denial of service (DoS) attack and proposed a enhanced scheme on Lee et al.´s scheme. Unfortunately, Ku et al. pointed out that Yoon et al.´s scheme can not achieve backward secrecy and is vulnerable to off-line password guessing and stolen-verifier attacks. In this paper, the other security flaws of the scheme that new insider attack and replay attack are stated, and an improved hash based scheme on Yoon et al.´s scheme is proposed. The improved scheme in this paper can fix all the known security flaws of Yoon et al.´s scheme except for backward secrecy and is more secure and efficient for practical application in source constraint wireless networks.