Research On Key Technologies For Privacy Protection Continuous Neighbor Query In Location Service

With the development of electronic commerce and popularization of mobile devices, location-based services(LBS) is now playing an increasingly important role in mobile applications deployed in mobile devices. It provides convenience for users to query interesting geographic position information (e.g., nearest neighbor querying) swiftly and exactly. But at the same time, users inevitably carry the danger of privacy information (e.g., location privacy and query content) leakage with themselves. On the purpose of erasing the further thriving of LBS applications, privacy security is the point that have to be taken in concern. It becomes pressing to provide a scheme that can support location based query services without compromising users' privacy. In the paper, author contributed in several aspects as follow:(1) Characteristics of continuous queries are studied and induced along with the common manner of privacy leakages and related recent works. The further directions to solving continuous location privacy preserving nearest neighbor querying is pointed out to be the guideline of author's work.(2) According to the observation and summary concluded from mobile user moving characteristics, a solution on named query plan optimization based on the direction in LBS continuous k nearest neighbor queries is proposed. Maintaining records of the history calculation of directional minimum bounding rectangle (MBR) priority queue on the server side in order to reduce server computation effectively and provide protection of privacy at the same time. Finally, with the arrangement of several contrast experiment the validity of the scheme is confirmed.(3) For the majority of the existence of continuous query privacy protection scheme based on trusted third party, it is hard to find a third party that is trustable. Another problem lays in system performance bottlenecks caused by third party when it receives DoS attack. For the intention of solving these problems, the author presents a resolution questioning the third party in continuous query service and improving its efficiency. Credentials are introduced into the query system, guarantee information anonymous during the processing of interaction between the three:user, anonymous server and LBS server. Anonymous server is granted with the ability to distinguish real users and artificial simulated users against DoS attacks. There are also improvements in the handling process of anonymous server accordingly which improved the efficiency of the system as a whole.In order to verify the validity of the continuous query method proposed in this paper, experiments are arranged and the results are analyzed.