The paper addresses the challenges of privacy-preserving spatial data queries in cloud computing, where a large amount of spatial data is outsourced to cloud servers to reduce local storage and computing burdens. The main issues are the high computational and storage overheads due to the need for detailed query range information and the insecurity of existing schemes against known plaintext attacks. To solve these issues, the authors propose an enhanced Asymmetric Scalar-Product-Preserving Encryption (EASPE) scheme and a new unified index structure. They first introduce a basic Privacy-Preserving Spatial Data Query (PSDQ) scheme using EASPE and a Geohash-based R-tree structure (GR-tree) to reduce query time. The PSDQ scheme requires less information about the query range and achieves IND-CPA security. An enhanced version, PSDQ+, further improves efficiency by using the GR-tree and an efficient pruning strategy, achieving sub-linear search complexity. The paper includes formal security analysis and extensive experiments demonstrating the efficiency and security of the proposed schemes.The paper addresses the challenges of privacy-preserving spatial data queries in cloud computing, where a large amount of spatial data is outsourced to cloud servers to reduce local storage and computing burdens. The main issues are the high computational and storage overheads due to the need for detailed query range information and the insecurity of existing schemes against known plaintext attacks. To solve these issues, the authors propose an enhanced Asymmetric Scalar-Product-Preserving Encryption (EASPE) scheme and a new unified index structure. They first introduce a basic Privacy-Preserving Spatial Data Query (PSDQ) scheme using EASPE and a Geohash-based R-tree structure (GR-tree) to reduce query time. The PSDQ scheme requires less information about the query range and achieves IND-CPA security. An enhanced version, PSDQ+, further improves efficiency by using the GR-tree and an efficient pruning strategy, achieving sub-linear search complexity. The paper includes formal security analysis and extensive experiments demonstrating the efficiency and security of the proposed schemes.