As cloud computing represents a new computing model, there is a great deal of uncertainty about how security at all levels can be achieved. Data security becomes more important when using cloud computing at all "levels" is addressed. Users are allowed to store large amount of data on cloud storage. The various security issues related to data security, privacy, confidentiality, integrity and authentication needs to be addressed. Most of the cloud service providers store the data in plaintext format and user need to use their own encryption algorithms to secure their data if required. The data needs to be decrypted whenever it is to be processed. This paper focuses on storing data on the cloud in the encrypted format using fully homomorphic encryption and proposes an extension to partial homomorphic scheme. It results in low size cipher text and choice is taken from the user. Intelligence has beenproposed to this scheme by the selecting automatically any of the algorithms – partial, fully or small cipher text size depending on the data or application.

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Data security; Cloud computing; Fully Homomorphic encryption; Public Cloud; Cipher text.