Optimization of User Identification Scheme with Preserving User Anonymity

Anonymity is a fine security characteristic for supplying user identification and key agreement along the user's login operation. Hsu and Chuang recently suggest A Novel User Identification Scheme with Key Distribution Preserving User Anonymity for Distributed Computer Networks. This paper presents a weakness of security that is found in Hsu and Chuang protocol. It is shown that this protocol attacker can freely impersonate the user or service provider. This occurs because an attacker can get the secret key of user (or the service provider) after successful execution of the key generation phase. It is shown a progress to improve and repair the security flaws of the Hsu and Chuang protocol and suggest that the proposed scheme is secure reply attack, impersonation attack and deniable of service(DoS).