A trigger-based pseudonym exchange scheme for location privacy preserving in VANETs

Location privacy plays an important role in Vehicular Ad Hoc Networks (VANETs). Pseudonym is normally used to preserve location privacy, which can meet the requirements of both privacy and security. When the same pseudonym is constantly used for a vehicle, the adversary can easily track it. To improve location privacy, a lot of pseudonym change schemes have been proposed. However, the tracker can match vehicles by the beacon message when it has found that the pseudonym is changed. Besides, every vehicle must hold lots of pseudonyms to change in these schemes. In this paper, we propose a trigger-based pseudonym exchange scheme, which aims to thwart to track vehicle from the sending beacons and reduce the storage consumption. We propose two trigger-based algorithms to decide when and how a vehicle exchange pseudonym with others. To evaluate the performance of our scheme, we conduct the probability of exchanging pseudonym in a road segment and a traffic intersection, and measure the tracking percent by an empirical tracker. The simulation results show that our scheme is resilient to confuse the tracker efficiently.