Data integrity is one of the biggest concerns with cloud data storage for cloud user. Besides, the cloud user’s constrained computing capabilities make the task of data integrity auditing expensive and even formidable. Recently, a proof-of-retrievability scheme proposed by Yuan et al. has addressed the issue, and security proof of the scheme was provided. Unfortunately, in this work we show that the scheme is insecure. Namely, the cloud server who maliciously modifies the data file can pass the verification, and the client who executes the cloud storage auditing can recover the whole data file through the interactive process. Furthermore, we also show that the protocol is vulnerable to an efficient active attack, which means that the active attacker is able to arbitrarily modify the cloud data without being detected by the auditor in the auditing process. After giving the corresponding attacks to Yuan et al.’s scheme, we suggest a solution to fix the problems.
Public Proof of Retrievability Scheme against Active Attack in Cloud Storage
