Ciphertext Retrieval System For Cloud Storage Based On Homomorphic Encryption Over Integers

Cloud Computing has become a hot topic in the field of information technologytoday. The convenience, economy, high scalability and many other advantages ofcloud computing make it wide attention and highly valued in industry, academia,government and other sectors. When the core task of the cloud computing are datastorage and management, cloud computing becomes a Cloud Storage systemproviding the functions of data storage and service access.In order to ensure the security, the data in the cloud is stored as ciphertext.Usually ciphertext retrieval system uses keyword matching technology for data valueretrieval, however, when the input keyword is a range of values, keyword matchingtechnology cannot be effective.In this paper, a retrieval system based on homomorphic encryption is proposed.The retrieval of the range of the ciphertext values can be achieved usinghomomorphic encryption scheme. Homomorphic encryption algorithms today,however, is very complicated, inefficient, and hasn’t got any practical application.On the basis of the analysis and comparison of existing homomorphic encryptionalgorithms, this paper selects one of them applied to the system, and using thehomomorphic encryption algorithm designs a retrieval algorithm, effectivelycompletes the retrieval of the range of the ciphertext values. This paper selects XMLto build a structured index file, and the attribute value of the element is the ciphertextof the word indexed from the source file. Only the attribute value of the element in theindex file is to be retrieved. The structured property of XML is easy for the retrievalto be implemented. It not only ensures the security of the source file, but also can getthe data user wants quickly and efficiently. For the condition that the homomorphicencryption algorithm in this paper is symmetric encryption algorithm, the RSAencryption algorithm is used to create a session key. Using the secondary keymanagement strategy ensures the security of the retrieval process. To further ensure the security of the system, MD5authentication technology combined with Salt valueis used to ensure that the user logged in the retrieval system is legal.Eventually the paper implements the ciphertext retrieval system based onhomomorphic encryption over integers on the basis of the research of the abovetechnologies. The system can protect the security of the data on cloud platform whilewell accomplishing data retrieval tasks.