An efficient public batch auditing protocol for data security in multi-cloud storage

Cloud storage enables users to remotely store their data. However, this new paradigm of storage service also makes the integrity protection of outsourced data a very challenging issue. Recently many integrity auditing protocols have been proposed, but most of them focus on the single cloud environment or don't support batch auditing. In this paper, we propose a public batch data integrity auditing protocol for multi-cloud storage. In the protocol a third party auditor can simultaneously verify the multiple auditing requests from different users on distinct data files stored on different cloud storage servers. By utilizing homomorphic cipher text verification and recoverable coding approach, the proposed protocol not only provides privacy preserving public auditing for data integrity, but also achieves quick identification of corrupted data. With the batch auditing, the total auditing time can be reduced and the communication cost is also low. Extensive security and performance analysis show the proposed protocol is secure and efficient.