VDPSRQ: Achieving Verifiable and Dynamic Private Spatial Range Queries over Outsourced Database

Private Spatial Range Queries (PSRQ) over outsourced data services have been widely applied in various practical scenarios in recent years. However, prior schemes that support dynamic updates cannot ensure both forward and backward privacy. Verifiable schemes incur high verification overheads. In this paper, we propose a verifiable and dynamic PSRQ scheme (VDPSRQ) to address these two issues. First, we define PSRQs over the outsourced database and define the forward and backward privacy for VDPSRQ. Then, we index outsourced databases using a G-tree and propose a two-kind Intersection Predicate Encryption (IPE) to implement efficient and forward-backward private PSRQs. Moreover, we design a lightweight completeness mechanism for results based on the RSA accumulator and G-tree. Through rigorous security analysis, we prove that our scheme can not only protect forward and backward privacy, but also guarantee security under chosen-plaintext attacks. Comprehensive experiments over a real-world database demonstrate the efficiency and feasibility of our scheme. Compared with baselines in terms of search and verification, our scheme is 200× faster, with only 76.2% verification time cost.