Design And Implementation Of A Location Privacy Protection System For Location-based Service

Nowadays, location-based services(LBS) have become more and more popular. Despite of the great convenience LBS brings to people’s life, its risk on personal privacy cannot be ignored. This paper mainly discusses the design and implementation of a location privacy protection system.Firstly, introducing the location privacy, analyzing features of existing privacy protection method and structure, the architecture of anonymous sever is selected. And further benefit with K-anonymous model and pseudonymous thought, both the location and identity of user can be protected.Secondly, considering the large space redundancy of traditional anonymous space algorithm of K-anonymous model, a system model based on grid and density is put forward in this paper. With the neighborhood expansion or edge contraction of grid search space, a more accurate minimum contain space is obtained.Thirdly, analyzing the trajectory privacy issue in continuous location service, the dynamic pseudonyms algorithm based on grid and density model is proposed. By giving a pseudonym for the requesting user, and exchanging the pseudonym of a high risk user with an adjacent user, the user trajectory is confused. With a mixed trajectory, it is hard for attackers to track users in continuous location service.Finally, the proposed algorithm and system is verified with actual trajectory data. Results tell that the algorithm enjoys great advantages on anonymous success rate and anonymous quality over the traditional IC algorithm, and the system can meet the real-time demands.