Research On Key Technologies For Location Privacy Protection In Vehicular Ad Hoc Networks

Vehicular Ad Hoc Network(VANET)is a special instantiate of mobile ad hoc network contains both vehicle nodes and stationary Roadside Units(RSUs).It opens a new door to facilitating road safety and traffic management.However,it also attracts tremendous privacy concern,such as tracing.Due to high privacy sensitivity of drivers,the huge scale of vehicle number and open essence of vehicular applications,VANET can not adopt the existed privacy preservation method in the traditional network scenarios.Therefore,studying on privacy preservation becomes a fundamental requirement in VANET.This paper is for the topic of privacy preservation in VANET.We analyze the critical challenges and key technologies systematically and focus on the most pressing issue of location privacy in VANET.A prevailing way to achieve the location privacy in VANET is by enabling vehicles to periodically change their pseudonyms when they are broadcasting safety messages.As a vehicle uses different pseudonyms on the road,its location privacy can be guaranteed by the unlinkability of pseudonyms.However,if a vehicle changes its pseudonyms in an improper occasion,pseudonyms changing may become useless for protecting location privacy,since an adversary could still link a new pseudonym with the old one.For this issue,the main work in this paper includes:A pseudonym change scheme based on capacity finite social spots is proposed achieve the location privacy in VANET,and then we develop an anonymity set analytic model closer to the reality quantitatively investigate the location privacy that is achieved by the proposed scheme.We present numerical results to illustrate the anonymity level achieved in the pseudonyms changing at social spots in terms of anonymity set size.The results show that some vehicles can not enter the social spots to change pseudonym for location privacy since the capacity of social spot is finite.We also propose a cooperative pseudonym change scheme based on the number of neighbors and the age of vehicle's pseudonym to improve anonymity,and then theoretically analyze the performance of the scheme in relatively simple one-lane VANET through mathematics.The proposed scheme has solved many issues of pseudonym change,such as low security and some restrictions of geographical location.In this paper,we discuss the influences of some parameters on the size of anonymity set in one-lane VANET through simulation,such as the traffic density,the communication distance R and the number of neighbors in the basic trigger k.By numerical results comparison,the performance of the scheme we proposed is better than the cooperative pseudonym change scheme only based on the number of neighbors.