Research On Ciphertext Fulltext Retrival Echnology For Cloud Storage

With rapid development of cloud computing, cloud storage has been more andmore popular and the one of the most common used services because it is cheap,convenience and extensive, many research and business organizations have foreseethe bright future of this area and started to provide their own cloud storage servicessuch as Baidu, Tencent and so on. In order to protect the privacy of users’ data, oneof common solution is that encrypting users’ sensitive data and storing theciphertext in the cloud side. Since the cloud storage providers often provide users alarge amount of storage space, users are also inclined to store their data in the cloudside. If the data is stored in the cloud side as ciphertext forms, when the dataamount increases to a large scale of data, users hardly search and locate whatdocument they need to find, especially when the network bandwidth is not enough,therefore, it is necessary for us to research on how to search and locate files.Actually, research on this topic is of significant value for research and business.However, a vast majority of nowadays technology are aiming to the problem ofdatabase ciphertext retrieval. Hence, the problem of ciphertext full-text retrieval incloud storage remains unsolved. Additionally, the database of cloud storage ifoutside the firewall, the keys of it need to be safely storage. As the third-partyproviders use internet to access cloud storage service, the client frequentlycommunicates with the server, safety and efficiency is of main concern.In order to solve the problems mentioned above, this thesis proposed severalalgorithms to either upgrade the performance of retrieval process or to optimizesome kernel technology. The mainly contents of this thesis are as follows:(1) In order to resist the attack based on statistical analysis, regarding thecharacteristics of indexed key words, this paper proposed an encryption method thatthe generate hash value basing on optimized hashing algorithm;(2) This thesis proposed a multiple hash algorithm to resist reverse attacks andto improve the security of the system;(3) This thesis proposed ciphertext full-text retrieval systems, it basic functionsof the full text of the ciphertext system through experimental results verify theoptimized algorithm can guarantee security, while maintaining high efficiency.Experimental results showed that the system of cloud storage technology hasachieved the basic needs and improve the efficiency and safety.