FRSA:An Efficient Fine-grained Range Query Scheme For Spatio-temporal Cipertext Databased On Access Control

With the rapid development of network and computer technology,people are exposed to a large amount of information,and to reduce storage costs,individuals or enterprises choose to store data on cloud server,thereby saving local storage and computing costs.Range query is a basic query in location-based services,that combines geographic location with service concepts.Users can use their phone’s location system to obtain their accurate location and generate location-related requests to be sent to the cloud server,such as querying surrounding malls,restaurants,etc.While range queries bring convenience to users,they also bring concerns about data security,and privacy protection for range queries is an urgent problem.Therefore,this thesis proposes an efficient solution based on access control and supporting fine-grained range queries to address the shortcomings of existing solutions on encrypted spatiotemporal data.The proposed solution adopts an improved k NN(k-Nearest Neighbor)algorithm,which allows data owners to adjust the data freely based on privacy or accuracy preferences,effectively preventing adversaries from repeating queries on the same random index.At the same time,under the action of a pseudorandom displacement function,adversaries cannot distinguish between fuzzy keywords and real keywords,further enhancing the security of encrypted data and avoiding information leakage.Secondly,the solution introduces polynomial fitting technology,first dividing any closed curve and selecting appropriate points for fitting,then extracting relevant information of the fitting curve and transforming it into vectors,and finally splitting and encrypting it to realize distance search for any closed curve.In addition,local storage overhead is significantly reduced during indexing and token generation.The proposed solution adopts a spatial data access control strategy to allocate user permissions,allowing each search user to access authorized data only,thus enhancing data security and avoiding information leakage.Finally,through game simulation between attacker Alice and challenger Bob,the security of the proposed solution was theoretically verified in terms of spatio-temporal data confidentiality,index and token privacy,and token indistinguishability.A large number of experimental analyses have shown that the proposed solution has more advantages in indexing,token,and query stages compared to similar solutions.