Public audit for operation behavior logs with error locating in cloud storage

To ensure the creditability of audit for operation behaviors in cloud storage scenarios, it is indispensable to verify the integrity of log files prior to forensic analysis. Thus, in this paper, we mainly focus on how to achieve effective public audits for operation behavior logs. To achieve this goal, we first propose a new block-based logging method to satisfy all necessary requirements for security and performance, i.e., tamper resistance of log files, non-repudiation of behaviors and selective verification of log blocks. Next, we give a privacy-preserving public auditing method for a single log block, which can support an unlimited number of effective auditing operations. Further, we present a binary auditing tree-based public auditing method, which can achieve error locating while supporting selective verification for multiple log blocks. The security of the proposed scheme is formally proven. Moreover, its performance for verification is evaluated by comprehensive experiments and comparisons with existing schemes. The experimental results demonstrate that our scheme can efficiently achieve public verification for operation behavior logs in the cloud storage scenario and outperforms the existing ones in computation and communication costs.