Efficient Identity-Based Multiple Copy Integrity Auditing Scheme for Cloud-Based IoT

Cloud-based Internet of Things (IoT) allows cloud users to achieve data outsourcing storage and flexible data access, which greatly eliminates the pressure on users to store and manage data locally. However, one risk behind this convenience is that untrusted cloud server may delete data rarely accessed or conceal the corruption of stored data to maintain its reputation. In order to verify the integrity of data remotely, a large number of public auditing protocols have been proposed. Moreover, to avoid the irreparable loss caused by data corruption, some multi-copy auditing schemes are also put forward where cloud users store multiple data replicas instead of single copy on cloud server, so that original file can be recovered from some intact replicas. In this case, how to check the integrity of multiple copies meanwhile considering the computation overhead of the auditor has become an important issue. In this paper, we propose a novel identity-based multi-copy integrity auditing scheme IBMCIA using indistinguishability obfuscation technique, which transfers most verification overhead from the auditor to the cloud server. Our IBMCIA scheme is constructed practically in medical scenario where electronic health records contain sensitive information and need to be preprocessed before uploading them to the cloud server. We introduce the role of hospital information center to implement tag generation and access management for alleviating the computation burden of patients. We prove the unforgeability of proofs under the CDH assumption and give the detailed performance evaluation.