LBSs privacy preserving for continuous query based on semi-honest third parties

Location based systems are becoming prevalent in recent years, many Location Based Services (LBSs) require users providing exact location information, due to the privacy concerns, the link between queries and users should not be disclosed. In this paper, we present a distributed query privacy preserving scheme involving multiple semi-honest servers, based on which, a novel query privacy preservation algorithm considering the moving status and trend is proposed. The service quality is taken into account to improve the clients´ service experience. To improve the efficiency and practicality, the algorithm only employs the query issuing clients to generate cloaked regions at one time for several clients. Due to the privacy concerns caused by clients´ dynamics, a location predicting mechanism is introduced. Finally, the evaluation metrics including privacy guarantee, quality of service, and system performance are presented. The simulation results show that our algorithm can preserve mobile user´s privacy as well as provide high Quality of Service (QoS).