A location privacy protection method based on cipher-text retrieval in cloud environment

In order to improve the efficiency of location query and the effect of privacy protection in cloud environment, a location privacy protection method based on cipher-text retrieval was proposed. Firstly, the spatial area is divided into several square grids, and the big Morton code of each location is calculated, the spatial area in the grid is divided again, and the small Morton code of each location is calculated. Secondly, the location data is encrypted by the combination of public key encryption and scrambling encryption, and then outsourced to the cloud server. When querying the location data of the interest points, the query request is sent to the data owner. After obtaining the query trapdoor and the private key, the query trapdoor is sent to the location data server for query. On the server side, the interest points in the region are found according to the cipher-text matching, and the cipher-text top-k sorting is implemented. Finally, the cipher-text query results are decrypted into plaintext by the private key. Experimental results show that the proposed method ensures the location data privacy, and improves query efficiency. At the same time, the balance between privacy protection security and query quality is achieved.