Ensure cloud storage correctness based on public auditing mechanism

Cloud service is not only for store the data in cloud but also for shared data over cloud for users. The integrity of data on the cloud be easily lost or damaged. To ensure cloud storage correctness based on distributed storage integrity auditing mechanism it helps to secure and efficient operations on cloud data done by third party auditor (TPA). The third party auditor utilizing the ring signature and keyed hash based message authenticating code for checking integrity. The data privacy and identity privacy on shared data is secured using private key encryption during auditing process by public verifier. In existing process the data freshness is not proven. So, we propose HMAC mechanism to protect the metadata secrecy, integrity, authentication on shared data in the cloud storage. This also supports random checking process by the public verifiers instead of checking the entire data on the cloud. Our audit system define the data freshness by secrecy, integrity, and authentication of metadata and also supports low computation and communication, less extra storage for audit the metadata.