A Systematic Literature Review on Privacy Preservation in VANETs: Trends, Challenges, and Future Directions

Privacy preservation is a fundamental requirement in vehicular ad hoc networks (VANETs) because it addresses sensitive vehicle and driver data. The use of pseudonyms instead of actual vehicle identities is one way to protect vehicle owners from the unauthorized tracking or linking of vehicle movements. In this paper, we conduct a systematic literature review to identify the implementation of pseudonyms in existing privacy preservation schemes via the Kitchenham method. To our knowledge, no study has presented an analysis of the implementation of comprehensive pseudonym life cycles in the last 5 years. We classify VANET system models and their advancements with the support of emerging technologies, mapping the integration of these technologies to the implementation of the pseudonym life cycle. Furthermore, we categorize the privacy analyses employed in existing schemes. Finally, we identify research gaps and future research directions to advance the development of robust privacy preservation schemes in VANETs. Of the 594 reviewed research papers, 113 satisfied our requirements for primary research (PR). Among them, 71% adopted VANET standard system models, 12% implemented a comprehensive pseudonym life cycle, and 73% conducted both formal and informal security and privacy analyses. We highlight research challenges and suggest future research topics for developing robust privacy-preserving schemes in VANETs.