ALPS: Achieving Accuracy-Aware Location Privacy Service Via Assisted Regions

Location search services (LSSs) provide convenience and enhanced functionality of ubiquitous computing, but they lead to a new risk of private location data leakage. The existing approaches generally use obfuscation to protect location privacy by perturbing the user’s location. However, this strategy inevitably degrades the accuracy of LSSs and affects the quality of service. In this paper, we propose an achieving accuracy-aware location privacy service via assisted regions, named ALPS, to protect user location privacy while ensuring the accuracy of services. Specifically, we devise two novel mechanisms (assisted regions mechanism and query obfuscation mechanism) to protect the user’s location privacy and ensure the accuracy of LSSs based on trilateration. The assisted regions mechanism prevents the attackers from getting the exact location of the user by protecting the user’s location within the overlapping region formed by the assisted regions. The query obfuscation mechanism obscures the user’s query content to prevent the attacker from predicting the user’s location based on the query content; the distance between the user and the query contents is calculated locally based on trilateration and the user’s location to ensure the accuracy of the LSSs. Theoretical analysis and experimental evaluation demonstrate that our scheme can protect location privacy without compromising the accuracy of LSSs.