2PASS: Bandwidth-Optimized Location Cloaking for Anonymous Location-Based Services

Protection of users' location privacy is a critical issue for location-based services. Location cloaking has been proposed to blur users' accurate locations with cloaked regions. Although various cloaking algorithms have been studied, none of the prior work has explored the impact of cloaking on the bandwidth usage of requested services. In this paper, we develop an innovative result-aware location cloaking approach, called 2PASS. Based on the notion of Voronoi cells, 2PASS minimizes the number of objects to request, and hence, the bandwidth while meeting the same privacy requirement. The core component of 2PASS is a lightweight WAG-tree index, based on which efficient and secure client and server procedures are designed. Through threat analysis and experimental results, we argue that 2PASS is robust and outperforms state-of-the-art approaches in terms of various metrics, such as query response time and bandwidth consumption. We also enclose a case study of 2PASS in a real-life application.