A Caching-Based Privacy-Preserving Scheme for Continuous Location- Based Services

With the rapid pervasion of location-based services (LBSs), location privacy protection has become a critical issue. In most previous solutions, the users get the query result data from the LBS server and discard it immediately. However, the data can be cached and reused to answer future queries. In this paper, we propose a caching-based solution to protect location privacy in continuous LBSs. Our scheme adopts a two-level caching mechanism to cache the users' result data at both the client and the anonymizer sides. Therefore, the continuous query user can directly obtain the query result data from the cache, which can reduce the interaction between the user and the LBS server to reduce the risk of user's information being exposed to the LBS server. At the same time, we propose the cloaking region mechanism based on the move direction of the user to improve the cache hit ratio. Security analysis shows that our proposal can effectively protect the user's location privacy.