The Research On Group Key Agreement Protocols In Ad Hoc Networks

The continuous development of network technology offers convenience for thereal-time communication based on open network, but the security issues attendant onthis should not be overlooked. In an open network, key establishment is an importantmechanism to ensure the safety of the follow-up communication. Via using thesession key obtained by key establishment protocol, participants can build a securechannel in an open network, so as to guarantee the security of information transmitted.As one of the key establishment protocols, key agreement protocol allows participantsto establish a common session key together. Although this way has the defect ofrelatively large amount of computation and communication, key agreement does notrequire a reliable third party and a secure channel, and the participants of theagreement need not trust other participants either. In this thesis, we select group keyagreement in Ad Hoc network as a research project. We have first studied the featuresof Ad Hoc network and security issues involved. Then, aiming at the securityvulnerabilities of undetectable online dictionary attacks existed in password-basedgroup key agreement protocol by Byun and Lee, we put forward a practical andefficient group key agreement protocol. We have also investigated the scalability ofgroup key agreement protocol in order to achieve the application of group keyagreement in large-scale network. And finally we propose a practical fault-tolerantgroup key agreement protocol, which is extensible.Depending on the summarization of the common group key agreement protocolattacks and the corresponding design principles and the concept of scalability of Adhoc network group key agreement protocol and expansion means, the main findings inthis thesis are listed as follows:(1) We studied a new password-based group key agreement protocol proposed byByun and Lee and found that this protocol can not resist the undetectable onlinedictionary attacks. Based on this finding, we proposed a new group key agreementprotocol. Security analysis shows the new protocol can resist on common attacks inpassword-based group key agreement protocol.(2) We put forward a new fault-tolerant group key agreement protocol andstudied its scalability on the basis of the cluster-based structure. The new protocol canachieve the safety of participants with lower calculation complexity. Meanwhile, it has characteristics of fault tolerance and reusability of long-term private key. Thesession key agreement analysis has shown that the majority of the new protocol canresist common attacks.