Four-Party Encryption Key Exchange

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 assists in generating a session key, were proposed. Once the clients are under diverse circumstances, they have to be authenticate by their own server. That is, it needs four-party to complete this protocol. In this paper, we focus on the four-party authenticated key exchange protocol, and presents four-party EKE.