Research On Service Query Privacy Protection Based On LBS System

In the information age of the combination of mobile network and location technology,the Location-Based Service(LBS)has been recognized by a large number of users.These service systems often collect,analyze,and process user data under the premise of the user's knowledge,so as to obtain users' private information.Therefore,how to protect users' private information without affecting the quality of LBS service has become the current research hotspot.Service requests based on the LBS system can be divided into two categories: static query and dynamic query.Static query refers to the query request issued by the user in a static state,which needs to protect the user's location privacy and query privacy;dynamic query refers to the query request issued by the user in a moving state,which needs to protect the user's trajectory privacy.The main research content of this paper is divided into two parts.(1)For static queries in the LBS system,a LBS service privacy protection scheme based on differential privacy is proposed.The scheme contains two kinds of privacy protection algorithm: users' location privacy protection algorithm and users' query privacy protection algorithms.The users' location privacy protection algorithm divides the map using Voronoi diagram,chooses l false location points based on k-means algorithms and l-diversiy idea,and protects users' location privacy with the Laplace mechanism.Based on k-anonymous algorithms,the users' query privacy protection algorithm builds the query k-anonymous set according to the neighbor users' query requests at the same time t in the cluster and the historical query probability of the region's POI,and protects users' query privacy with the Exponential mechanism.Through setting the privacy protection intensity of the algorithm by the users,the generated location data set and query k-anonymous set can resist a variety of attacks from malicious attackers.Theoretical analysis and experimental results show that the scheme can effectively protect the location privacy and query privacy of users.(2)For dynamic queries in the LBS system,a LBS trajectory privacy protection scheme based on differential privacy is proposed.The scheme combines k-anonymity algorithm with differential privacy protection mechanism,taking into account factors such as road network accessibility,time,speed,historical access probability and historical transition probability,to construct k-anonymity sets for stop points,query points and destination points in the trajectory respectively and protect users' sensitive points in the trajectory.Experimental results show that the scheme can better protect the privacy of users' trajectories,and it is superior to other schemes in terms of LSP utility and data availability.