Comments on Chaotic Maps-Based Password-Authenticated Key Agreement Using Smart Cards

In 2012, Guo and Chang proposed a chaotic maps-based password-authenticated key agreement scheme. Their scheme uses smart cards and Chebyshev chaotic maps to enhance the security. After analyzing Guo and Chang's protocol, we find that their scheme does not provide forward secrecy and integrity is absent in password change phase. In this paper, details of the found flaws and some further suggestions are given.