基于区块链的公平可靠密文检索系统

With cloud computing seeing rapid advances, users tend to transfer massive data from local server to cloud servers, and the data should be encrypted as ciphertext and then stored on the cloud. Searchable Encryption (SE) is a technology allowing data retrieval in ciphertexts based on keywords. However, SE defaults the server to an honest entity, yet if it is maliciously transformed, data retrieval turn out to be deficient in fairness and reliability. To overcome this deficiency, this study focuses on Public-key Encryption with Keyword Search (PEKS) and then introduces an enhanced blockchain-based PEKS. Firstly, the general architecture of the newly developed system is built on the ciphertext retrieval and features of blockchain. It consists of 4 sections including client side, retrieval, smart contract, and server side, and operates when these sections interact. Fairness and reliability of the system depend on the smart contract controlling participants in data retrieval. Security analysis is also carried out, justifying the system is valid in keyword privacy, fairness, and reliability. Finally, based on above mentioned scheme, the blockchain-based PEKS system is realized, and the performance test and analysis prove that the system is feasible and practical.