Research On Data Secure Storage And Query Methods For Cloud

With the rapid development of the Internet as well as the arrival of data intensive society, cloud computing and related technologies attract increasingly attention. Cloud computing combines the resources on the Internet as a unified entity, providing users with powerful computing resources and adequate storage space. While users enjoy the services provided by the cloud, they don’t need to care the process about data computing, storage and management on the cloud. Large-scale data is migrated from the user client to the cloud storage server, which greatly reducing the user’s burden about data management. However, once the data stored on the cloud server, the user won’t restrict the unauthorized operation from the cloud system. To protect data security, users store the data in encrypted form on the cloud. Although ciphertext storage improves security, it complicates the process of data query quickly.On the basis of a wide range of study and research on the application of encryption technology in cloud computing, especially, we research the ciphertext storage technology and ciphertext query technology. We proposed a model of data storing and querying securely, and elaborate the theory model from the aspects of ciphertext storage and ciphertext query. This model guarantees the confidentiality, integrity of the user’s data, ensures the effect of querying data and realizes data sharing. The specific works as follow:(?) Architecture and algorithm of ciphertext storage:We encrypt the full-text data with AES to protect the confidentiality of sensitive data and store the ciphertext on the cloud computing server. In order to ensure the effect of ciphertext querying, we conduct three steps as follows. First, we obtain the plaintext keywords by processing the original data and the weight of each keyword by computing the weight of the keywords. Second, generating the ciphertext keywords by encrypting the plaintext keywords. Last, gaining the ciphertext index vector by combination of the ciphertext keywords and the weight of the weight of the keywords. In the process of data storing, we store the ciphertext and the ciphertext index vector on the cloud computing server. In the whole process of data storing, the original data is stored in the format of ciphertext, which protects the users’ data effectively.(?) Architecture and Algorithm for ciphertext data query:To solve the problems of ciphertext storage and query on cloud, this paper proposes a ciphertext query algorithm according to the mutiplication homomorphic encryption characteristic of RSA. On this basis, this paper sorts and displays the ciphertext query result efficiently by using the calculation method of the ciphertext similarity, which is the combination of inclined angle’s cosine of vector, vector’s mapping length and words’ weight.(?) Finally, we implement a ciphertext data storage and query system for cloud computing according to the actual application demand for the digital content management system. We implement the architecture for ciphertext data storage and query to the digital content management system. At the same time, we verify the availability and reliability of the ciphertext data storage method. Finally, the ciphertext query time is investigated in a lab environment. The ciphertext query time is considered as acceptable to users.