Addition-Composition Fully Homomorphic Encryption is given inthis paper to solve data security equation in cloud computation. An earlierattempt to solve security problem has been proposed by Craig Gentry,who combined additive and multiplicative operations, using lattice-basedcryptography. Its construction started as a somewhat homomorphicencryption scheme that evaluates low-degree polynomials over encrypteddata. He then modified it to make it bootstrappable and showed that any bootstrappable fully homomorphic encryption scheme can be convertedinto a fully homomorphic encryption. Subsequent efforts to improve on Craig’s work still favor his approach, i.e. bootstrapping homo morphiccryptosystems with noisy ciphertexts into fully homomorphiccryptosystems. The approach in the design of the scheme in this paper is based on combining additive and composition properties making itcomplex to compromise. Finally, the scheme enables secure computationof cloud data without exposing it to deliberate risk.