Research On Secure Channel Free Searchable Encryption Technology

In recent years, cloud computing and cloud storage technology are progressing rapidly. Due to its low cost management and convenience, more users start to store the data in the cloud environment. In order to protect the confidentiality of sensitive data files, the files always are encrypted before being stored in the cloud. Since searchable encryption scheme can achieve secure data sharing and support user to execute keyword search over ciphertxt without decryption operating, the searchable encryption has become the focus of cloud computing encryption system.The thesis focuses on the secure channel free searchable encryption technology. Identity-based secure channel free searchable encryption was proposed by combining secure channel free keyword searchable encryption with identity-based technology. Identity-based encryption can reduce computing overhead of public key management and the cost of storage. Security proof of our scheme is presented, and then performance analysis and experiment simulation is performed. Furtherly, attribute-based secure channel free searchable encryption is proposed by combining attribute-based encryption and secure channel free searchable encryption. In this scheme only the user who matches the access structure can successfully search the corresponding keyword files. The access structure of this encryption scheme is based on LSSS(linear secret sharing matrix). It not only supports fine-grained access control, but also has high computational efficiency. Security proof about our scheme is present, and performance analysis and simulation are also completed. As two schemes are based on secure channel free, trusted channel between the user and the server need not to be established. The schemes can significantly reduce system overhead, and have more practical value.