Efficient pseudonym changing schemes for location privacy protection in VANETs

To achieve location privacy for Location-Based Services (LBS) in the Vehicular Ad-hoc Network (VANET) environment, many pseudonym changing mechanisms have been proposed in the literature. Although some exiting mechanisms, such as AGE, SLOW, SPOT and can achieve high security level, yet much overhead is incurred due to a large number of pseudonym changes. While performing pseudonym changes, the services from the location server will be interrupted and the routing has to be reestablished, causing communication overheads. In light of this observation, this study proposes efficient pseudonym changing schemes to minimize the number of pseudonym changes while still achieving high location privacy protection level. Criteria for performing pseudonym changing are proposed by considering the age of pseudonyms, the speed, and the moving direction of the vehicles. Thus, four mechanisms AS, AD, SD and ADS are developed by using the combination of these three factors. Simulations have been carried out with the SUMO simulator. Compared with other existing pseudonym changing approaches, simulation results show that the proposed mechanisms have better performance in the sense of achieving high protection rate with less number of pseudonym changes, and, in particular, ADS always has the best performance.