Processing private queries based on distributed storage in location-based services.

With the rapid development of global positioning system, cellular networks and relative technologies, people can request location-based services (LBSs) from the service provider using a handheld device quickly and easily. This greatly facilitates people's life. However, it brings a lot of privacy leakage problems. To reduce it, many methods have been proposed. But, they still don't balance the intensity and efficiency of privacy protection very well. Based on distributed storage and the quadratic residual theorem, this paper proposes a LBS user privacy protection scheme with both security features and efficiency. The traditional encryption method, private information retrieval (PIR), will bring high communication cost and computing pressure on the server side. A distributed storage system architecture can greatly reduce network overhead and the risk that the server will identify the user's real location because requests can be answered by the caching proxies without arriving at the server. To enable encrypted requests to be answered correctly by the caching proxies without being known by proxies, we build an index table. Compared with the similar work, simulation results show that our scheme can effectively reduce user communication and server computing overhead.