Research On Location Privacy Protection Based On Grid Partition

With the development of mobile Internet and location technology,location-based service has become an important part of adults' daily life.In the process of requesting services,untrusted LBS servers can launch inference attacks through users' personal information,query preferences and other background knowledge to obtain user privacy.In the existing kanonymous privacy schemes,researchers mostly consider the algorithm of selecting virtual locations from users' historical locations to construct anonymous regions,without considering user attributes such as query frequency,access probability and so on.The LBS server can speculate the user's current location information based on the historical data from long-term statistics.Therefore,in order to ensure that the historical query data and query frequency of users will not be obtained by attackers,based on the full analysis of the existing methods,this paper proposes an anonymous region partition algorithm based on grid and a privacy protection algorithm for continuous query.In this paper,a grid repartition algorithm based on query frequency is proposed.The main idea of this algorithm is to give weights to the pre-divided grid by genetic algorithm,and to extend the grid by greedy strategy for the cell in which the user is located.The adjacent grid expansion method is used to expand the cells that are not included in the anonymous region.Through grid repartition,the query frequency of each anonymous region after expansion is basically the same.At the same time,the accuracy and stability of the algorithm are compared with other similar algorithms through experiments,and the influence of spatial gridding accuracy on the application of the algorithm is analyzed.Based on caching mechanism and multiple katakana strategy,this paper further optimizes the grid repartition algorithm and proposes a privacy protection scheme which can be used for continuous query.This scheme can not only meet the different privacy needs of users,but also protect the privacy information of users during continuous query.The main purpose of this scheme is to establish a collection of collaborative users in the anonymous area after grid rezoning.Collaborative users can choose whether to upload query information and query results to the cloud,and users can obtain query results through cloud cache information when requesting services,so the frequency of sending query requests to LBS is reduced to a certain extent.When the user cannot get the required information in the cache information,the multiple Kana mechanism is combined to make the user use different Kana as the user name when sending the query,so as to resist the inference attack of the attacker.Because the attacker cannot connect two different user names to the same user within a period of time,the multiple katakana mechanism can effectively protect the privacy and security of users.In addition,this paper further analyzes and verifies the effectiveness of the algorithm through theoretical analysis and experimental verification.With the help of central anonymity and cooperative users,the grid repartition algorithm proposed in this paper can quickly construct anonymous regions,and the grid-based continuous query location privacy protection algorithm can also be based on grid repartition.Effectively resist the long-term statistical attacks and privacy leakage caused by users constantly requesting services during the mobile process.Finally,the algorithm proposed in this paper is verified by experiments on Gowalla and Foursquare data sets,and compared with other algorithms.Through theoretical analysis and experimental results,it is proved that the privacy protection algorithm proposed in this paper not only overcomes the weakness that users are vulnerable to long-term statistical attacks and reasoning attacks in the process of continuous query,but also improves the efficiency and speed of anonymous region construction.at the same time,it also reduces the query error to a certain extent.At the same time,the experimental results also prove that the grid-based privacy protection algorithm proposed in this paper has good effect and high efficiency when users send continuous requests.