PrivacyZone: A Novel Approach to Protecting Location Privacy of Mobile Users

While location-based services and applications are increasing in popularity, there are growing concerns over users' location privacy. Although there exist general purpose mobile permission systems and cloaking techniques, these techniques suffer from several problems when applied to continuous location and GPS access, as they are often rigid, coarse-grained, not sufficiently personalizable, and unaware of road network semantics. This paper proposes PrivacyZone, a novel system for constructing personalized fine-grained privacy quarantine regions and protecting users' privacy within these regions. PrivacyZone allows users to seamlessly enter their privacy specifications under spatial, temporal, and semantic customization. Novel challenges arise from having to enforce privacy zones for large volume and variety of users with frequent location updates. We show that naive privacy zone processing techniques are inefficient and cause excessive energy consumption. We therefore develop advanced processing techniques based on the concept of safe hibernation. We empirically evaluate our techniques to demonstrate their trade-offs with respect to hibernation time, computation effort, and network bandwidth usage. Our results show that PrivacyZone is efficient, scalable, and flexible, while preserving users' location privacy.