Research On Online/Offline Attribute-Based Multi-Keyword Searchable Encryption

With the rapid development of internet information technology and mobile electronic devices,cloud storage of data files was born and has become the first choice.However,storing data files directly in cloud may meet the risk of data leakage.To overcome that,one effective way is to upload encrypted data files to the cloud.Therefore,how to implement data sharing and retrieval mechanisms for cloud encrypted files is a big challenge.For the problems we mentioned above,we first propose an online/offline attributebased multi-keyword searchable encryption supporting boolean queries.In order to realize the access control to the database,we adopt the method which is the combination of online/offline attribute encryption and outsourcing decryption,based on the linear secret sharing access structure.In this scheme which can be applied to mobile electronic devices,not only the file owner has an efficient online encryption efficiency,the download user also has a fast decryption efficiency.In addition,this scheme,supports keywords authorization and boolean function queries as well.Furthermore,due to the situation that the server may tamper with data files or search dishonestly when someone uses the paid server to search,we propose an online/offline attribute-based multi-keyword searchable encryption scheme with smart contract.In this scheme,search results are verified by bilinear mapping accumulator,and the fairness of the transaction is guaranteed by the smart contract on block chain.The download users can ensure the fair payment even in the "pay first,use later"transaction mode.