In this chapter, to enable vehicles to achieve high-level location privacy in VANETs, an effective pseudonyms changing at social spots (PCS) strategy is proposed. In the PCS strategy, the social spots are the places where many vehicles temporarily gather. First, the chapter utilizes the unique feature of social spots, i.e., where many vehicles temporarily stop at the social spot, to propose the PCS strategy.
In addition, as an important technical preliminary of PCS strategy, the chapter presents a practical key-insulated pseudonym self-delegation (KPSD) model, which securely generates many on-demand short-life keys and can mitigate the hazards due to vehicle theft. Second, the chapter takes the anonymity set size (ASS) as the privacy metric to measure the quality of privacy (QoP) achieved in PCS strategy. The chapter uses the simplified game-theoretic techniques to formally prove the feasibility of the PCS strategy.