A Novel Pseudonym Changing Scheme for Location Privacy Preservation in Sparse Traffic Areas

Large number of schemes have been proposed to deal with location privacy preservation in VANETs. One of the most popular ways to preserve location privacy is pseudonym changing, which includes mix-zone, silent zone, mix-context zone and trigger-based schemes. The pseudonyms must be changed after a specific interval to preserve location privacy. All of these schemes require vehicles to be a part of dense traffic in order to change a pseudonym. Although pseudonym changing schemes are not computationally expensive and ensure location privacy preservation, a huge drawback is that these schemes are suitable only for dense traffic areas, they do not apply to sparse traffic areas. Another drawback is that these schemes do not prevent from colluding attacks. In this research, we propose a scheme, called LPSA (Location Privacy in Sparse Areas), that allows pseudonym changing schemes to work in areas where traffic is not dense. A sparse traffic area is where traffic density is lower as compared to mix-zone, silent-zone and mix-context zones. LPSA does not require traffic to be dense for private pseudonym changing. This makes it suitable for both dense and sparse traffic areas. For location privacy preservation in dense areas, we utilize mix-context zones, while we modify pseudonym changing scheme to preserve location privacy in sparse areas. LPSA also provides protection from colluding attacks. Our results show that LPSA provides better traceability, average anonymity set size, pseudonym change per trace and average confusion in both sparse and dense traffic areas.