Secure Data Outsourcing on Cloud Using Secret Sharing Scheme

Data Outsourcing in Cloud (DOC) has its exclusive benefits like low-cost, lower management overhead, elasticity of storage etc and these encourage organizations to use cloud computing to outsource massive amount of data to the cloud providers. The outsourced environment of the cloud and its inherent loss of control cause risk of exposing highly sensitive data to internal or external attacks. Traditionally, the data are kept encrypted to have secure authorized-only access. But, encrypting and decrypting large data files are computationally costly. Hence, secret sharing based DOC schemes have emerged due to their low complexity. Here, the proposed scheme uses simple Boolean based encryption and decryption of the data files (only image-files are considered in this paper) which is low in computational cost. The encrypted data files will be shared on the cloud. A threshold (t, n)-secret sharing scheme applied on the symmetric key of the encryption algorithm. The n share-keys will be generated from the secret key and will be distributed among participants. If t or more (≤ n) shared-keys are submitted, the original data files can be retrieved. Hence, it allows a threshold authorized-group of t or more data-users.