Integrity as a service for replicated data on the cloud

Summary With the proliferation of cloud storage services, data integrity verification becomes increasingly significant in order to guarantee the availability and correctness of the outsourced data. Recently, many auditing schemes have been proposed to verify data integrity without possessing or downloading the outsourced data files. However, such schemes in existence assume that there is a single data owner that can update the file and compute the integrity tags. They do not consider the efficiency of user revocation when auditing multi-owner data in the cloud. In addition, existing schemes only support dynamic data operations over fixed-size and single-copy data blocks. Thus, every small update may need updating the tags for all file blocks in all replicas, which in turn causes higher storage and communication overheads. This paper proposes a public and dynamic auditing scheme that supports fully dynamic data operations over variable-size data blocks for replicated and multi-owner cloud storage. Moreover, the proposed scheme can also support efficient user revocation. By supporting batch auditing, the proposed scheme can handle multiple auditing tasks simultaneously and divide an auditing task into multiple sub-tasks in order to increase the detection probability. Experimental results prove the effectiveness and efficiency of the proposed system. Copyright © 2016 John Wiley & Sons, Ltd.