Abstract: Geo-fencing technology is widely used in recommender systems, advertising push and other services. It has serious risk of personal privacy leakage threat. Focus on triggered query in Geo-fencing, the theories of the secure tripartite computation were applied in the research of the LBS privacy-preserving model, which follows the concept of location obfuscation and location k-anonymity and reaches the target of user's identity unlink-ability and location's untraced-ability. Location anonymity hidden problem and secret authentication problem were solved by computational geometry techniques and principles of cryptography in the triggered queries scenario. Theoretical analysis shows the model is security. From the perspective of privacy-preserving, the attackers do not get new knowledge from LBS system. Experiments demonstrate the computational efficiency and communication loads of this medel are superior to the traditional spatial-temporal cloaking methods.

Key words: secure tripartite computation, geo-fencing, location-based services, privacy-preserving, triggered query