Research Of Searchable Encryption Technique In Cloud Storage Environment

With the rise of cloud computing, cloud storage is becoming increasingly popular. The market size of cloud storage is expanding, mass private data have been entrusted by more and more individuals or companies to cloud service providers for storage. Cloud users are most concerned about data security issues, namely, data confidentiality, integrity and availability. Users may not fully trust cloud providers, therefore, they may be reluctant to adopt cloud storage service from vendors to store their files and data. Various types of cloud storage platforms have solved most security issues, but less attention has been paid to data confidentiality. Data confidentiality includes not only traditional technologies, but also potential safety issues and technologies brought by the specificity of cloud storage, such as cipher text cipher text queries and access control. In consequence, searchable encryption technology is becoming a hot spot both at home and abroad, which is also the main research question in this thesis.First of all, this thesis has proposed a new efficient scheme for public key encryption with conjunctive keyword search, together with the detailed process of this scheme and the realization of algorithms in all stages. This scheme can use public channel for transmission with less linear operation. This has improved the execution efficiency for algorithm, proved the consistency from theory, and conducted the analysis of algorithm security.Then, based on the new proposed encryption scheme, this thesis has designed a retrieval system applicable to many searchable encryption algorithms. Its C/S framework based retrieval system, with plug-in and layer structure to satisfy users’requirement on plaintext encryption and cipher text retrieval. The system designed doesn’t bear the need for public cloud service providers. It ensures the confidentiality and integrity of data and realizes fire sharing. One prominent merit is that, if a problem appears in a cloud service provider, the user data keeps safe since all data are encrypted. Users don’t need to worry about providers’ illegal obtaining their data.Finally, this thesis conducted performance verification to the design of the system and the sensitivity of system to document size is not high. The advantage of searchable scheme on this cloud storage is significant, enabling users to keep control of data security when using public cloud as well as its performance.