Earticle

Recently, with the dramatic popular of geo-social networks and location based services (LBS), more and more mobile users are willing to enjoy the proximity services, which is a friend-alarm when the buddies happen to be in proximity. However, the services provider (SP) and some compromised buddies could try to steal the user’s exact location information. Hence, location privacy preserving is still a challenge question in proximity based services. Unfortunately, existing methods only consider Euclidean distance to calculate neighbors, which would bring great deviation for distance measurement in the actual terrain. To my knowledge, this article is the first time extending to the 3D surface and proposes a novel technique for the privacy-preserving proximity services. The technique utilizes simplicial triangulation decomposition on 3D surface, and the user's location is generalized with a triangular area space, then a more precise proximity distance measurement method based on the triangle fractal is proposed. Next, we design a privacy-preserving proximity query protocol, which provide complete privacy with respect to the SP and the buddies. Final, the experiments shows that our methods have practicality in the services quantity and privacy.