Research On Authenticated Key Exchange Protocol Based On Diffie-Hellman Method

The design and analysis of authenticated key exchange protocol is an important problem in information security area, and play an important roal in computer network technology. In recent years, with the rapid development of computer network technology and the wide range applications of the Internet, how to ensure secure communications between parties in such an open channel has aroused extensive attention from scholars. The two party authenticated key agreement protocol can make communicating parties to negotiate a shared session key in the public insecure channel, then the session key can be combined with a variety of password mechanisms to ensure the safety between both sides of the communications, to establish a secure channel between two communicating parties.As a formal analysis methods based on computational complexity, with a clear definition of the security attributes and semantic computing, provable secure method has become a main tool of the study about various cryptography and protocols. In the analysis of the security of protocols, provable security which reduces the protocol security to a "well-known" cryptographic algorithms or a mathematical hard problem makes the security of protocol more credible.In this paper, We analysis some encryption mechanisms especially Hash function and its difference between Ideal model and Standard model. Then we introduced the security assumptions including the discrete logarithm and related some of the Diffie-Hellman problems. With a further study on two party authenticated key agreement protocol and provable secure method, we make some main word and some contributions as follows:1. With twining key technology we propose a new two party key agreement protocol TUP which is obtained by modifying the UP protocol, then in conjunction with the trapdoor test method, we prove strictly that the new protocol is secure in eCK model. Compared with previous protocols, the security assumption of new proposal is more standard and weaker, it also solve an open problem in ProvSec’09.2. We give a definition about a new encryption scheme:extended One-Way Function. Then we propose a new two party key agreement protocol without using this (postponed) ephemeral key derivation to achieve the security, and prove strictly that the new protocol is secure in eCK model. Compared with previous protocols, the new proposal is more reliable as the technique it used is less.3. Since Password protocol is vulnerable to dictionary attacks, in this paper, we proposed a simple and symmetrical two-way authentication key agreement protocol with dominant mutual authentication, in the greatest extent possible to avoid password attacks. Then we proved its security in the BPR modle.