Privacy Preservation and Service Provision in Geo-spatial-temporal Systems

The main aim of Location Based Services (LBS) is to ensure user privacy whileproviding the best LBS for users. There are very few works focusing on the tradeoffbetween location privacy preservation and location query information gathering whichare used to improve the LBS in future. Privacy preserving Location Query (PLQ) is onesuch technique, however its quality of service is very low and its inability to identify theunreachable areas in the user obfuscation area can cause problems to user privacy. Inaddition to this, the untrusted Location Based Server (LBSr) can malfunction andperform other attacks like maximum movement boundary attack, shrink region attack,user query privacy attack to identify or track the user.In this thesis, we propose the Privacy preserving Geometric Aware Location Query(PGALQ) algorithm which collects the aggregate information of user queries and alsoprovides geometric aware obfuscation by eliminating unreachable areas. We also extendPGALQ with Pseudonym and Multiple Query Confusion Algorithm (PMQCA) to preventLBSr to launch the above mentioned attacks. The results of the proposed algorithm iscompared with the algorithms mentioned in the literature which shows that our algorithmperforms efficiently.Computer Scienc

X.Meng. Protecting Location Privacy against Location-Dependent Attack in Mobile Services

Privacy preservation has recently received considerable attention for location-based mobile services. In this paper, we present location-dependent attack resulting from continuous and dependent location updates and propose an incremental clique-based cloaking algorithm, called ICliqueCloak, to defend against location-dependent attack. The main idea is to incrementally maintain maximal cliques for location cloaking in an un-directed graph that takes into consideration the effect of continuous location updates