Improvement of HWWM-authenticated key agreement protocol

Recently, Hsu et al. showed that Ku and Wang''s authenticated key agreement protocol is vulnerable to the modification attack and then proposed an improved protocol, called HWWM protocol. In this paper, we argue that the HWWM protocol is still vulnerable to the modification attack and cannot also withstand the password guessing attack. Then, we propose an improved protocol to solve these problems. [Copyright &y& Elsevier]