An improved multi-copy cloud data auditing scheme and its application

The security of the data in the cloud server suffers great challenges, and how to ensure the integrity of the outsourced data in the cloud servers is a problem that should be solved. Cloud data auditing technique is such a solution, which allows to check data integrity without retrieving them from the cloud. In case single-copy data may be violated by malicious attackers, Zhang et al. proposed a multi-copy cloud data auditing scheme MCAM in 2020. However, in their scheme, an attacker can forge the evidence for integrity verification only by exploiting public information and the cloud server can compromise the integrity verification even it does not store any data. In this paper, we identify these security flaws in MCAM and design a new evidence verification algorithm to fix them. Then, we propose a multi-copy cloud data auditing scheme based on our evidence verification algorithm and MCAM. In security analysis, we prove that our multi-copy cloud data auditing scheme can fix the security flaws of MCAM. Thus, our scheme is more secure than MCAM. In performance analysis, we show that our scheme is more communication efficient than MCAM. Finally, we point out one potential application of our scheme.(c) 2023 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).