Data can be stored in cloud and also shared among multiple users. But the correctness of data present in the cloud may be in doubt as there exists human errors and also some hardware/software failures. Cloud data can be audited by both data owners and public verifiers. Many mechanisms exist through which data can be audited efficiently for checking reliability without retrieving the entire data from the cloud server. But, public auditing for checking the integrity of shared data will predictably reveal some private information about the identity to public verifiers. Therefore a unique mechanism to preserve identity privacy which supports public auditing for the shared data that is stored in cloud is proposed. Here ring signatures that are required to compute verification metadata for auditing the integrity of shared data are exploited. With this mechanism, the shared data integrity can be efficiently verified without retrieving entire file by not disclosing the identity of the signer on each block to the public verifier. Instead of verifying one by one , the mechanism will also perform multiple auditing tasks simultaneously.