Interlock protocol

Abstract: The purpose of the Diffie-Hellman protocol is to enable two users to exchange a secret key securely that can then be used for subsequent encryption of messages. The protocol itself is limited to exchange of the keys. But because of having no entity authentication mechanism, Diffie-Hellman protocol is easily attacked by the man-in-the-middle attack and impersonation attack in practice. In this paper, we compare the computational efficiency of various authentication methods. Finally an improved key exchange schema based on hash function is given, which improves the security and practicality of Diffie-Hellman protocol.

Abstract: A key agreement protocol is used to derive a shared secure session key by two or more parties, but no party can predetermine the resulting value. Users can securely exchange information over an open network by using the shared session key to encrypt/decrypt secure information. Recently, several key agreement protocols based on chaotic maps are proposed. Xiao et al. proposed a novel key agreement protocol based on chaotic maps and claimed their protocol can resist the known attack which is proposed by Bergamo et al. However, Han et al. and Xiang et al. pointed out that the Xiao et al. protocol is still insecure. To overcome these attacks, we shall propose an extended chaotic maps-based key agreement protocol. The proposed protocol not only can resist these attacks, but also provide mutual authentication and user anonymity.