A Dual Privacy Preserving Scheme in Continuous Location-Based Services

To address the risk of location privacy disclosure in location-based services (LBSs), existing solutions generally introduce a single trusted anonymizer between the users and the location service provider (LSP). However, a single anonymizer offers limited privacy guarantees and incurs high communication overhead in continuous LBSs. Once the anonymizer is compromised, it may put the user information in jeopardy. In this paper, we propose a dual privacy preserving (DPP) scheme in continuous LBSs to protect the users' trajectory and query privacy. Our scheme introduces multiple anonymizers between the users and LSP, and combines with Shamir threshold mechanism and K-anonymity technology to improve the users' trajectory and content privacy in continuous LBSs. An anonymizer alone cannot get the users' trajectory and query contents, and it thus can be semi-trusted. Our scheme can enhance the users' privacy and solve the single point failure in single anonymizer structure. The security analysis demonstrate that the proposed scheme has the ability to protect users' trajectory and content privacy effectively.