Abstract
Key exchange protocol is important for sending secret messages using the session key between two parties. In order to reach the objective, the premise is to generate a session key securely. Encryption key exchange was first proposed to generate a session key with a weak authenticated password against guessing attacks. Next, another authenticated key exchange protocols for three-party, two clients who request the session key and one server who authenticates the user's identity and assist in generating a session key, were proposed. In this paper, we focus on the three-party authenticated key exchange protocol. In addition to analyzing and improving a password-based authenticated key exchange protocol, a new verified-based protocol is also proposed. © 2003 Elsevier Inc. All rights reserved.