Ensuring Data Security in Cloud Computing using Homomorphic Encryption

Cloud computing is the most interesting and new technology which offers computing as service rather a product to its clients on demand through Internet. Since cloud computing provider stores the data and distributed resources in the open environment, however the major issues in cloud computing is the security of the data being stored in the cloud and privacy while the data is being transmitted to and from a cloud organization. We can use traditional encryption algorithms (like, AES, DES, TDES, and RSA etc.) to secure the storage of data in cloud provider. But they don’t allow to perform operations on encrypted data without giving the private keys to cloud remote server. So; there is a need for new mechanism to perform on ciphered data which provide data security such as confidentiality and privacy for cloud service users. Homomorphic encryption is a form of security technique which allows to execute computations on ciphered user’s data without having to decrypt and produce an encrypted result which, when decrypted, it is same as the result when operations performed on the plaintext. In this paper, paillier homomorphic algorithm is applied on encrypted data, MD5 algorithm for authentication and one time password for verification of identity is used. Thus, result of confidentiality and privacy of cloud client data are achieved through paillier homomorphic encryption and OTP and also proposed system allows cloud service provider to perform computations on encrypted data without knowing the secret key.