A Flickering Context-based Mix Strategy for Privacy Protection in VANETs

Vehicular Ad-Hoc Networks (VANETs) are a significant part of Intelligent Transportation Systems (ITS), and they are used to enhance the road safety and improve the traffic efficiency through the communication between vehicles and roadside units. However, some malicious adversaries can use the periodically broadcast beacons in VANETs to track vehicles. To mitigate this threat and protect privacy, existing research primarily suggests the use of pseudonyms as variable identities for each vehicle, and has explored different pseudonym mix strategies. These mix strategies often introduce latent traffic accident risks by requiring the vehicles to change their driving behavior or stop broadcasting. In this paper, we present a flickering context-based mix strategy, which can reduce such hidden dangers and provide higher privacy level than traditional context-based strategy. Besides, we employ a passive global adversary to evaluate the proposed strategy and conduct simulations in both virtual maps and real city maps to measure the protection level of the proposed privacy scheme. Finally, the influences of different parameters in our new method are explored.