LPPS: A Distributed Cache Pushing Based K-Anonymity Location Privacy Preserving Scheme

Recent years have witnessed the rapid growth of location-based services (LBSs) for mobile social network applications. To enable location-based services, mobile users are required to report their location information to the LBS servers and receive answers of location-based queries. Location privacy leak happens when such servers are compromised, which has been a primary concern for information security. To address this issue, we propose the Location Privacy Preservation Scheme (LPPS) based on distributed cache pushing. Unlike existing solutions, LPPS deploys distributed cache proxies to cover users mostly visited locations and proactively push cache content to mobile users, which can reduce the risk of leaking users' location information. The proposed LPPS includes three major process. First, we propose an algorithm to find the optimal deployment of proxies to cover popular locations. Second, we present cache strategies for location-based queries based on the Markov chain model and propose update and replacement strategies for cache contentmaintenance. Third, we introduce a privacy protection scheme which is proved to achieve k-anonymity guarantee for location-based services. Extensive experiments illustrate that the proposed LPPS achieves decent service coverage ratio and cache hit ratio with lower communication overhead compared to existing solutions.