Authenticating Top-k Queries in Location-based Services with Confidentiality

State-of-the-art location-based services (LBSs) involve data owners, requesting clients, and service providers. As LBSs become new business opportunities, there is an increasing necessity to verifythe genuineness of service results. Unfor-tunately, while traditional query authentication techniques can address this issue, they fail to protect the confidentiality of data, which is sensitive location information when LBSs are concerned. Recent work has studied how to preserve such location privacyin query authentication. However, the prior work is limited to range queries, where private values only appear on one side of the range comparison. In this pa-per, we address the more challenging authentication prob-lem on top-k queries, where private values appear on both sides of a comparison. To start with, we propose two novel cryptographic building blocks, followed by a comprehensive design of authentication schemes for top-k queries based on R-tree and Power Diagram indexes. Optimizations, security analysis, and experimental results consistently show the ef-fectiveness and robustness of theproposed schemes under various system settings and query workloads.