CPESP: Cooperative Pseudonym Exchange and Scheme Permutation to preserve location privacy in VANETs

Abstract In VANETs, vehicles exchange information to/from the surrounding entities (vehicles, infrastructure, network, device, pedestrian) in wireless mode for various safety and non-safety applications. This Vehicle-to-Everything (V2X) wireless communication poses privacy risks because it can be exploited to collect the vehicle's trajectories. Preserving the location privacy is an essential aspect in a vehicular network. Various pseudonym changes-based privacy-preserving schemes have been proposed to protect location privacy in VANETs. However, when evaluated using essential privacy metrics in the simulation, the performance of these schemes found low. In this paper, we propose an enhanced scheme called Cooperative Pseudonym Exchange and Scheme Permutation (CPESP) to preserve the users' privacy in a VANETs. In our schemes, we allow vehicles to exchange their pseudonyms cooperatively and propose a novel mechanism where like pseudonym the schemes can also be changed (permute) by vehicles to create confusion for the adversary that can further improve the privacy. Since we are exchanging the pseudonyms between vehicles, it also eliminates location tracking by service providers. We evaluate the strength of our proposed scheme and compare it with existing mechanisms on a PREXT simulation platform. We use several popular privacy metrics such as anonymity set size, entropy, traceability, normalized traceability, and average confusion for comparison. Simulation results reveal that our scheme has the great potential to preserve the location privacy in VANETs and can also be enhanced to deliver much better than the existing schemes.