Public data integrity auditing without homomorphic authenticators from indistinguishability obfuscation

Cloud storage services allow users to outsource their data to remote cloud servers to relieve from the burden of local data storage and maintenance. Despite the benefits, data outsourcing has also made the data integrity protection in cloud storage a very challenging issue. Plenty of public auditing schemes have been proposed, which allow a third-party auditor to check the data integrity on behalf of users. However, most of these schemes are constructed on homomorphic authenticators, which require strong computation capability on the user side and incur high storage overhead. In this paper, a novel public data integrity auditing scheme is proposed from indistinguishability obfuscation. In our scheme, each user processes the entire data to be outsourced by using only symmetric key primitives, and the server only needs to store the outsourced data. In comparison with existing works, the proposed scheme frees users from the heavy burden on calculating the authenticators and reduces the storage overhead significantly. Moreover, we show the security of the proposed scheme with rigorous proofs. Finally, the performance analysis and comparison with existing works demonstrate the proposed scheme achieves better performance in terms of data processing cost on the user side and storage overhead.