Cryptanalysis of Lee-Hwang-Li's Key Authentication Scheme
Key authentication is very important in secret communications and data security. Recently, Lee, Hwang and Li proposed a new public key authentication scheme for cryptosystems with a trusty server. However, in this paper, the authors will show that Lee-Hwang-Li's key authentication scheme is not secure, from the obtained public information, any one can get the private key of the user. And then, they propose an improved scheme. They conclude that their new key authentication scheme not only resolves the problems appeared but also is secure.