Research And Implementation Of Distributed Trust Scheme For Vehicular Ad Hoc Network Based On Blockchain

As the infrastructure of intelligent transportation,vehicular ad hoc network technology has a very important position in modern transportation.Its application and development have made great contributions to the improvement of traffic efficiency and safety.However,due to some open features of the ad hoc network,it still has many problems in terms of trust management and privacy protection,that is,it is difficult to judge whether the road messages sent by the vehicle are reliable while protecting the privacy of the vehicle.Therefore,in view of the existing problems of vehicle-based ad hoc networks,this thesis proposes a blockchain-based trust management model and combines an anonymous vehicle announcement protocol.First,for privacy issues,an anonymous vehicle announcement protocol based on ring signatures was designed to allow vehicles planning to broadcast road messages to seek witnesses to vote on the messages,and then send the aggregated package containing the opinions of the witnesses to the roadside unit(RSU)for the message verification of credibility.The protocol includes privacy protection schemes,and authority agency will provide pseudonyms for each vehicle based on the true identity of the vehicle to provide privacy protection.Further,the use of ring signature during vehicle communication hides the pseudonym of the vehicle to prevent malicious vehicles from being tracked and monitored,and authority agency can track malicious vehicles to prevent malicious vehicles from using the privacy protection function to avoid accountability.Next,for the reliability and synchronization of existing reputation data,a trust management model based on blockchain is proposed.The model consists of trust computing and hybrid consensus algorithm.In trust calculation,RSU relies on a weighted voting mechanism to determine the credibility of the message,decide whether to broadcast the message,and update the vehicle’s reputation value based on the logistic regression method.Considering the unique characteristics of the blockchain,such as distributed,tamper-proof,consensus,etc.,a blockchain that combines Proof of Work(Po W)and Practical Byzantine Fault Tolerance(PBFT)algorithm is designed to allow all RSUs to jointly manage the vehicle’s reputation data,where Po W nodes are responsible for mining and PBFT nodes are responsible for the verification of new blocks.Finally,through theoretical analysis and simulation experimental tests,it is proved that the proposed scheme can effectively complete the privacy protection and trust management work in the vehicular ad hoc network,and the mixed consensus algorithm designed in the protocol has higher efficiency than the traditional consensus algorithm.