One-time password authentication scheme using smart cards providing user anonymity

In 2005, Lee and Chen proposed an improved one-time password authentication scheme that can prevent a stolen verifier attack and that is as efficient as the scheme of Yeh-Shen-Hwang. The current paper, however, demonstrates that Lee-Chen's scheme is still vulnerable to Denial-of-Service attacks and a simple solution is presented in order to isolate such a problem. Furthermore, we propose an efficiently optimized one-time password authentication scheme that can provide user anonymity. In addition the computational costs are lower than those of Lee-Chen's scheme.