Research On Key Technologies Of Preserving Location Privacy In Location Based Services

With the development and popularization of the Internet and the mobile devices,a variety of mobile applications have changed our lifestyle tremendously.Location-based Services(LBSs)are increasingly implemented in mobile application develop-ment in order to provide end users personalized experiences,by benefiting from the mature growth of positioning technology.The heavy usage of location information be-ing used by mobile applications raises public concern on location privacy,which also draws academic attentions.Privacy in LBSs is different from the traditional application scenarios:First of all,there is a tradeoff between the quality of service and the loca-tion privacy.LBSs often require users to provide accurate,real-time and continuous location information to ensure the quality of services,in the meanwhile,such location information causes privacy risks because the LBS providers are not always trustwor-thy;Additionally,the location information is used to identify personal identity as well as acquiring location data.An anonymous user can be tracked and leads to exposure of his/her real identity using such information.In the prime time of LBSs,the real challenge is how to strike the balance between protecting the privacy of the location data and ensuring the quality of service.This paper surveys the traditional techniques in preserving privacy in LBSs,and analyzes functional characteristics in different processes of using LBSs,and introduces a novel privacy preserving method for each process.Firstly,unlike most of the privacy preserving methods which treat the quality of service and the location privacy as a zero-sum game,this paper argues that a good tradeoff should find a new balance point,which means to enhance privacy without reducing the quality of service;Secondly,most of the traditional methods shouldn't restrict the functionality of LBSs for general appli-cability,however in order to increase the privacy of location information will result in compromising the quality of service without restrictions in place.In contrast,there are also some methods which are designed for application-specific scenarios,and can propose optimum tradeoffs,however they are often based on strong assumptions on the functionality of LBSs and therefore are not applicable to general LBSs.This paper focuses on different aspects of using LBSs and explores functional characteristics of these processes without losing generality,in order to guide our research in preserving privacy in LBSs.The main innovations and contributions of this paper are listed as follows based on the above ideas:·For the process of information querying,proposes a novel path confusion method to anonymize users of LBSs.This method allows nearby users to confuse their paths with each other to increase privacy,and without reducing the quality of services.·For the process of Information sharing,proposes a novel cryptography scheme which can encrypt private location and geographic information.Using attribute.based encryption,users with a same location attribute can share geographic in-formation with each other;while other users and the LBS server cannot decrypt such information,thereby ensures privacy and the quality of service at the same time.·For the process of positioning,proposes a novel fingerprinting estimation algo-rithm.This algorithm can be performed at third party servers,to generate public location fingerprints and enable positioning at the client side,thereby ensures privacy.·Designs and implements a LBS privacy preserving tool set PP-T and the cor-responding privacy server.Evaluates the privacy performance of this tool set using a test case on the core mechanism.The test case uses a smart office LBS application,which contains the basic functions of LBSs and is a typical LBS ap-plication.The results to some extent indicate that the methods used in PP-T are feasible and effective.