Comparative Study on Preserving Data Integrity for Shared Data in Cloud Storage

Abstract

-A novel privacy-preserving mechanism that supports public auditing for shared data stored on cloud. " Ring Signatures " is a technique to compute authentication metadata required to review the accuracy of shared data. This mechanism precise that the identity of the signer on each block in shared data is hidden from public verifiers, who are able to proficiently verify shared data integrity without retrieving the entire file. Beside the mechanism is able to execute multiple auditing tasks simultaneously instead of verifying them one by one. And with data storage and sharing services in the cloud, users can easily transform and share data as a group. To certify that the shared data integrity can be verified publicly, users in a group need to calculate signatures on all the blocks in shared data. Blocks in these shared data are usually signed by different user due to data alterations performed by different user. For security measures, when user is revoked from a group, the blocks which were previously signed by the revoked user must be re-signed by an existing user of a group.