A Trajectory Privacy-Preserving Scheme Based on Dual-K Mechanism for Continuous Location-Based Services

With the development of wireless communication and positioning technology, location-based services (LBSs) have been gaining tremendous popularity, due to its ability to greatly facilitate the people’s daily lives. Meanwhile, it also entails the risk of location privacy disclosure. To address this issue, we usually adopt K-anonymity in the centralized architecture based on a single trusted anonymizer. However, it may expose the user’s privacy in continuous LBSs. In this paper, we propose a dual-K mechanism (DKM) to protect the user’s trajectory privacy for continuous LBSs. Our scheme introduces multiple anonymizers between the user and the location service provider (LSP), and each time the K query locations are sent to K anonymizers to form K-anonymity respectively. At the same time, we combine with location selection mechanism to confuse the user’s real location to enhance the user’s privacy. The LSP and a single anonymizer cannot get the user’s trajectory, and the anonymizers can be semi-trusted. The security analysis demonstrates that our scheme can effectively protect the user’s trajectory privacy.