Research On User Privacy Protection Technology For Location-based Services In Mobile Internet Environment

With the rapid development of the Internet and the maturity of domestic 4G,mobile terminals are rapidly becoming popular in people's lives.Location-based services have provided great convenience for daily life.While location-based services are convenient for people,they require users to expose their precise location information to location service providers.In the entire location-based services process,privacy of the user's identity information,points of interest,and precise location are at risk of being exposed.In order to ensure that the privacy information of users is not revealed when users are using location-based services,scholars have proposed numerous location privacy protection solutions.However,most of these solutions only protect the user's location privacy but ignore other privacy information such as the user's identity information and interest point types.The attacker can infer the user's exact location by obtaining the user's other private information.Many solutions assume that third-party anonymous servers are fully trusted,but in reality,third-party location servers are not fully trusted.Simply by protecting the user's location privacy can not protect the user's track privacy,and the user's location privacy and track privacy are easier to be seen by the attacker in road network environment.This thesis aims at multi-dimensionally protecting user's privacy and protecting user's trajectory privacy when users continuously request the service in road network environment.Hence,this thesis conducte in-depth research on road network environment,continuous query,location privacy protection architecture and classic location privacy protection algorithm.Specifically,the main work of this thesis is as follows:1.Considering the exposed privacy in road network environment and the crisis of trust about the third-party anonymous server,this thesis proposes an incremental query scheme based on the road network for location privacy protection.The scheme introduces the grid of latitude-longitude to solve the problem of untrusted third-party anonymous servers.The mobile terminal designs an anonymous set generation algorithm to solve the problem of exposing the interest type of the traditional method in continuous query.The anonymous server combines the road network environment and the characteristics of the grid of latitude-longitude to optimize the anonymous area generation algorithm,and a random loop circle minimum anonymous area generation algorithm is proposed in combination with road weights to further improve the service quality.Security analysis and experimental results show that this scheme improves the efficiency of user query services while satisfying the privacy requirements of users.2.In order to solve the problems of track privacy exposure when the user continuously request service in road network environment,this thesis proposes a road network grid of latitude-longitude scheme for user track privacy protection.This scheme takes the road direction and speed limitation of the road network into account,and then uses the road connectivity set and the anonymous user similarity to constrain the generation of the anonymous area to improve user privacy security.The security analysis and experimental results show that this scheme can improve the security of users and reduce the computational overhead in road network environment.The research shows that it is an effective method to improve the security of users' privacy protection in road network environment.The method combines the characteristics of geographic grid of latitude-longitude and road network environment to research multi-dimensional privacy protection of users and privacy protection of user locations during continuous query.The research results have a certain theoretical and practical reference significance.