Efficient homomorphic encryption using ECC-elgamal scheme for cloud data

In cloud computing data security plays important role. Most of the user stores their data on cloud. Cloud data security must satisfy the three goals of security-confidentiality, integrity and availability. This paper focuses on confidentiality goal. Generally data on cloud is not stored in encrypted form. It is because at the time of processing it needs to be decrypted. In homomorphic encryption user or application can be able to perform computation on encrypted data. Most of the homomorphic encryption algorithm generates large cipher text which makes processing inefficient. This paper focuses on homomorphic encryption using elliptic curve cryptography scheme. In proposed homomorphic encryption scheme the size of cipher text is considerably reduced due to its smaller key size with same level of security like RSA. User can perform the operation on this low size cipher text. So in this scheme, cloud data always in encrypted form and it will not get exposed in plain text.