Research And Implementation Of Trust Management Mechanism In VANET

Vehicular Ad-hoc Network(VANET)is a significant component of intel-ligent transportation system(ITS).With the help of the new generation of in-formation and communication technology,VANET realizes the all-round net-work connection between the vehicle,people,Roadside unit(RSU)and the ser-vice platform,which can effectively improve the road traffic safety and trans-portation efficiency.However,as a special mobile ad hoc network(MANET),VANET has the characteristics of openness,high mobility,dynamic topology and so on,which makes VANET suffer from various kinds of internal and ex-ternal security threats.Traditional security measures,such as authentication,signature and public key infrastructure(PKI),can only defense external attacks,while for authorized and authenticated attackers from internal,these methods are useless.Hence,experts and scholars propose to introduce "trust manage-went" into VANET to build the trust relationship among vehicles,then vehicles in VANET can avoid malicious vehicles and choose trustworthy vehicles to corporate with.In this paper,we mainly do the following research on the trust management mechanism of VANET.(1)A hierarchical trust management framework is proposed.Based on dif-ferent network entities in VANET,the framework is divided into three layers:vehicle trust management(VTM),domain trust management(DTM)and global trust management(GTM).The framework defines the functions and interrela-tions of each layer,and can effectively solve the problems of data collection,storage and management in the process of trust evaluation.(2)An anti-attack trust management scheme(AATMS)is designed.Specif-ically,a Bayesian inference based algorithm and a TrustRank based algorithm are designed,which are used to calculate the local trust value and the global trust value respectively.In the process of trust evaluation,AATMS considers direct historical interaction experience among vehicles and social factors of ve-hicles.Meanwhile,in order to satisfy the trust accumulation principle of "slow rise and fast fall",an adaptive forgetting factor and an adaptive decay factor are introduced to update the local trust value and the global trust value.(3)Experiments and analysis based on the Veins platform.The perfor-mance of AATMS and other VANET trust models are compared under no ma-licious attacks and malicious attacks(i.e.newcomer attack,on-off attack and collusion attack).The experimental results show that AATMS can efficiently identify trustworthy and untrustworthy vehicles in VANET even under a certain degree of malicious attacks.