Research On Group Key Management Scheme Of Vehicular Adhoc Network

VANET is the application of mobile ad-hoc network in intelligent transportation,as well as the important technical support of intelligent transportation and carnetworking industries. It has the basic characteristics of large scale delay-tolerantnetwork, i.e. wide network coverage, long delay of communication, intermittentinterlinkage of links, and multihop asynchronous transmission.VANET vehicle group is the logic set of a large number of OBU vehicle nodes inVANET network. It has relatively wide application scenarios in intelligenttransportation, such as running cars in a team, city bus group, taxi group, as well asthe realization of group conversation among many vehicles based on the group,anonymous authentication mechanism based on the group signature, and so on.The discussion and research on the VANET network group key managementmechanism of city blocks have practical significance, because the characteristics ofVANET network are communication asynchrony, transmission multihop and networkopportunity which is different from the Internet network, and the network scale is alsodifferent form Ad-hoc mobile ad-hoc network.This thesis firstly describes the basic theory and concept of security protocol,analyzing the communication mode and security of VANET vehicle group,establishing its communication and security model. It presents VANET group keymanagement plan based on random key distribution specific to the network,communication and topology characteristics of VANET, and analyzes the aspects ofsecurity and communication performance of plan. The plan mainly includes four parts,i.e. key data establishment, key divisor exchange, key data distribution and keyupdate. It adopts exchanging mode to establish key divisors among group managerand members, adopts negotiatory mode to generate key data, presenting key datadistribution mechanism based on constructing multinomial, and adopts HASH chainmode to periodically update the group conversation key.The security of key management plan based on random distribution can bereduced as the intractable problem of equation of higher degree described by largenumber factor decomposition, DDH computational hypothesis and Abel-Ruffinitheorem. The plan is able to guarantee the forward and backward characteristics, and support the group key recovery of the off-line vehicle nodes.Based on the randomly distributed key data transmission mechanism, the plan iscompared and analyzed with the classical group key protocol in the aspects ofcomputation, communication and storage. Although the complexity of the plan ishigher than the classical group key protocol, it’s able to effectively avoid the singlelocation invalidation caused by centralized distribution, and the problem of exorbitantcommunication round number brought about by fully distributed negotiation mode.Especially in the VANET network group with larger scale node number, whichcommunication overhead is able to be suitable for, the plan also supports to groupscale expansion.