Search and Permission Request Over Encrypted Database

Data sharing has become increasingly important in order for organizations to maintain competitiveness in the AI-empowered digital economy. Whereas, in the face of stringent data protection and privacy regulations, such data sharing needs to be designed with extreme care. This motivates the study of privacy-preserving data sharing schemes in distributed systems. In this work, we consider a basic scenario where shared data are stored in an encrypted database while still allowing for search requests and permission verification. In contrast to the scenario of existing SSE schemes, in our case, we consider the scenario where each file comes with an access function while each user has a dynamic attribute. So a file is returned to the requester if (1) The file contains the keyword that is being searched; (2) The requester's attribute values tuple in the time of query satisfies the access function of the files. We propose a scheme that is designed to satisfy these requirements and analyze its security and efficiency.