Research On Security Authentication And Location Privacy Preservation Of Vanet Based On Pseudonyms And Mix Zone

With the improvement of people's economic level,they have put forward higher requirements for the quality of life and are eager for more comfortable and fast ways of transportation.Therefore,the number of vehicles used has increased rapidly,which results in traffic problems such as traffic jams and traffic accidents and these problems have been widely concerned by the public.Vehicle ad-hoc networks(VANETs),as an important support for the Internet of Vehicles,were proposed and become the key to solve these traffic problems.VANETs take use of real-time vehicle to vehicle(V2V)communication,vehicle to road side unit(V2R)communication to make drivers better aware of road conditions and take early actions to avoid collisions,accidents,and traffic jams so that drivers can get a better driving experience.However,VANETs also face many security and privacy challenges in realizing these uses because of the openness of wireless communications.In the course of driving,the vehicles periodically broadcast safety messages including position,direction and time to the surrounding vehicles and RSUs.In order to ensure the messages secure and reliable,it is necessary to sign and verify the messages.At the same time,the drivers who broadcast the security messages are unwilling to disclose their own identity,location and other privacy information.However,once there are malicious messages,it is necessary to track their real identity and revoke them.Therefore,how to realize conditional privacy preservation authentication and location privacy preservation of vehicles in VANETs has become the focus of research.In this paper,we propose a conditional privacy preservation authentication scheme based on pseudonyms and Shamir secret sharing technology.This scheme implements anonymous communication of vehicles through unlinkable pseudonyms generated by two hash chains.For a controversial message,to prevent framed attacks on honest vehicles,the revocation mechanism based on Shamir threshold secret sharing is adopted.When there are the threshold vehicles report to TC,the malicious vehicle can be revoked.In addition,by leveraging two reversed hash chains,forward security and backward security are guaranteed,which optimize the revocation overhead.Simulation results show that our scheme outperforms other schemes in terms of communication overhead,authentication overhead and revocation overhead.Location privacy preservation is another research focus in this paper,and mix zone is an effective way to preserve location privacy.In mix zone,all vehicles change their pseudonyms at the same time to achieve confusion of vehicles' location information with K-1 neighbor vehicles to guarantee location privacy.When the number of vehicles cooperate to change pseudonyms does not reach K,how to establish K anonymity mix area to ensure location privacy is a problem.Our scheme solves the problem through the incentive mechanism based on the Stackelberg game,in which leader vehicle sets the incentive to stimulate follower vehicles to cooperate and generate more pseudonyms to meet K anonymity.Given a reward by leader vehicle,the follower vehicles compete to generate redundant pseudonyms until K anonymity and equilibrium is reached.From the perspective of attacker,there are K vehicles changing pseudonyms simultaneously.Besides,group signature technique is used to realize the secure communication during pseudonym changing.The simulation results show that the proposed scheme effectively implements K anonymous location privacy preservation under low vehicle density.