Research On Trajectory Privacy Protection Technology For VANET Nodes

LBS services are widely used in VANETs to provide various services.When continuous queries are requested from different locations,a trajectory will be formed.The trajectory essentially reflects the behavior of the vehicle as well as the driver and passengers.If the trajectory privacy is not protected,it will cause serious threat.So,the protection of vehicles' trajectory privacy is an urgent problem to be solved.This paper aims to explore the defects of the existing trajectory privacy protection technology.This paper uses a multi-anonymizer structure,by this structure,the attackers cannot obtain the vehicle's trajectory from a single anonymizer,which increases the difficulty of attackers.In addition,elliptic curve encryption and hash verification technology are adopted in response to attackers' attacks on the communication process in the system.For different usage scenarios,the following two solutions are proposed:(1)The Genetic Algorithm is used to predict the trajectory,and suitable shadow vehicles are selected based on the deviation of the predicted trajectory.Then,a number of fake queries are inserted into the queries of real vehicles and shadow vehicles,finally a query matrix is formed and sent it to the LBS server for query.Fake queries make vehicle's paths intersect,which can prevent the reverse mapping from vehicle's identity to query content,so that the attacker can't distinguish the complete trajectory of the target vehicle and the scheme can prevent continuous query attacks.Experiments have proved that the scheme improves the prediction similarity,the selected shadow vehicles are similar to the predicted trajectory of the real vehicle and the privacy protection of the trajectory is enhanced.(2)First,select the set of active candidate fake locations near the active road section,and then execute the fake locations selection algorithm to determine the final fake locations within the distance offset.These final fake locations are connected to each other to form false trajectories with high similarity to the real trajectory.Experiments have proved that even when the attackers have certain background knowledge,the location exposure and trajectory exposure of this scheme are still both reduced,and this scheme enhances the privacy of the vehicle's trajectory.