| Location-based services (LBS) means services relating to geographic location. Because of the location information of the user’s fully exposed to a location-based service providers, If the user’s location information or query information is used by some malicious ISP. It will damage to the personal and property safety of users. For example,the user requests service like this"nearest gynecological hospital", if the query is informed of the attacker who can deduced the information that this user is female and suffering from gynecological disease. So it is very necessary to study the privacy protection of location-based services.At present, space k- anonymity is widely used, when search the cloaking region just based on the count of users, and without considering the speed of the user and the actual distance factor.Given this issue, we make two factors to be considered, we propose a new solution of k-anonymous. In this paper three algorithms of searching the cloaking region have been proposed: bottom-up_grid_cloaking algorithm, top-down_grid_cloaking algorithm and hybrid_grid_cloaking algorithm. Research contents include: firstly, to solve the problem that the location anonymous server does not fully trusted , the paper presents the work of dispersed grid computing to the user terminal, the user reported to the server their grid ID instead of the exact location . Secondly, to solve the problem that when to update the information table, my paper claims that as long as the user’s grid ID changed then a update requests can be send. Then, the paper add user’s velocity and distance parameter to expansion of Anonymous regional and propose a new anonymous algorithm. The Description and the specific execution process of the algorithm be given. Finally, to improve the efficiency of our algorithm, the thought of buffering mechanism have been proposed, the user’s recently request information be stored, so we can use the hybrid algorithm that be proposed by this paper to search a new cloaking region based on the stored information.Using the data sets which generated by NG network node generator, design and implement experiment. The result shows that compared to traditional search methods, Experimental results show that our method improves the efficiency of anonymous algorithm and gets the quality of LBS services better. |
