International Journal of Network Security
Key authentication is very important in secret communications and data security. The researchers proposed a new public key authentication scheme for cryptosystems based on discrete logarithms in 2003. Recently, they pointed out that their scheme was not secure and proposed an improvement on it. However, in this paper, the authors will demonstrate that a dishonest user can forge the public key via the verification equation in the improved scheme. Therefore, their scheme does not achieve non-repudiation of the user's public key.