Privacy-Preserving Pseudonym Management and Change Scheme in Fog-Based VANETs

Abstract

Existing pseudonym schemes in Vehicular Ad-Hoc Networks (VANETs) incur significant communication and storage overhead. Moreover, while RSU-dependent schemes are constrained by the cost and scala- bility of infrastructure deployment, RSU-independent schemes frequently rely on centralized components that introduce both privacy vulnerabilities and performance bottlenecks. To address these issues, this paper proposes a fog-computing-based pseudonym-management architecture that utilizes distributed fog nodes to execute pseudonym generation, distribution, storage, and accountability. Within this framework, a vehicle entering a fog domain receives a pool of short-term pseudonyms from its nearest fog node for intra-domain communications. This architecture significantly reduces communication latency, alleviates the burden on the centralized certificate authority, and enhances system scalability. In addition, based on the proposed architecture, a vehicle-centric RSU-independent pseudonym-change mechanism is introduced. The mech- anism dynamically determines the optimal timing for pseudonym changes by quantifying driving-behavior similarity and incorporating real-time vehicle states such as speed, direction, and relative position. Theo- retical analysis shows that the proposed scheme provides effective privacy protection. Experimental results demonstrate that, compared with traditional RSU-based and centralized schemes, the proposed scheme sig- nificantly enhances anonymity while substantially reducing the risk of being tracked, offering a practical and scalable solution for privacy-preserving VANETs.