Achieving Absolute Privacy Preservation in Continuous Query Road Network Services

Abstract

Research have shown that location semantics have lead to privacy leakages especially when two or more users in a cloaked region depict similar semantic locations. This implies that, to achieve absolute privacy(query privacy, location privacy and semantic location privacy) protection for a client on road network, it is important that cloaked users have their locations distinctly diverse with diverse semantics, and making diverse service request thus satisfying the k-anonymity and l-diversity conditions for privacy. Unfortunately, the determination of semantic location of a mobile user online is a challenge which makes the achievement of absolute privacy protection more challenging. In this paper, we developed a privacy preserving algorithm that protects a client’s absolute privacy for continuous query road network services. We employed an offline trajectory clustering algorithm and semantic location graph to aid the selection of cloaked users that will effectively protect the absolute privacy of a client. We evaluated the effectiveness of our algorithm on a real world map with two defined metrics, and it exhibited an excellent anonymization success rate in a very good query processing time for the entire period of continuously querying road network services.