The security is primary need of any data storage system. In this work the cloud data storage and their security is the key area of investigation. The cloud data is always mobile by nature because the cloud infrastructure providers are host or move their data from one storage to another for reducing maintains cost of server. In this context the security and privacy of data is key concern or service provider and data owner. In order to keep secure data on cloud the cloud service providers to encrypt the data over server in cryptographic format. The cryptography is effective manner of security because it requires some key to recover the original data. But the key management policies and key generation techniques are key factor of deciding the security depth of any cryptographic cloud. The proposed work favors the Homomorphic key cryptographic technique for securing the data on cloud. Therefore the Paillier algorithm is proposed for implementing with the cloud. The Paillier algorithm is an asymmetric key encryption technique which first generates the pubic key and private key for securing the data. But the technique is not much suitable for the text data cryptography therefore the data is converted in two equivalent numerical value and the cryptographic operation is performed. After encryption the data is preserved on file on cloud storage. The security of the proposed cryptographic technique is demonstrated using the three applications i.e. file upload, download and the sharing of files among the cloud server users. The implementation of the proposed secure cloud hosting is performed on JAVA technology. After implementation the performance of the algorithm is computed in terms of time consumption, memory consumption, and server response time. The results demonstrate the proposed technique is acceptable for data hosting on cloud.

Cloud Computing Homomorphic Encryption Security Cloud Storage Cryptography Cipher-text and plaintext