Replication is a fundamental solution for the cloud service provider (CSP) to guarantee data availability. To provide users with convincing evidence that the copies required by them are all stored correctly, a number of multi-copy integrity auditing schemes were presented. Recently, Barsoum and Hasan proposed a map-based provable multi-copy dynamic data possession scheme (IEEE Transactions on Information Forensics and Security, vol. 10, no. 3, pp. 485_497, 2015), which was claimed to be secure and can ensure that the CSP possesses all copies required by the contract. However, in this letter, we show that the scheme is easily subject to a copy-summation attack and a single-copy attack, by which a cheating CSP only needs to invest a storage cost of a single copy—while can still pass the verifier’s challenge at all times. Therefore, the scheme is no longer secure in this case. Furthermore, we propose some simple but effective countermeasures and give a repaired scheme which is free from the above two attacks.

中文翻译：

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对__云计算系统中可移动的多副本动态数据持有的评论_


复制是云服务提供商（CSP）保证数据可用性的基础解决方案。为了向用户提供令人信服的证据，证明他们所需的副本都已正确存储，提出了多种多副本完整性审计方案。最近，Barsoum 和 Hasan 提出了一种基于地图的可证明多副本动态数据持有方案（IEEE Transactions on Information Forensics and Security, vol. 10, no. 3, pp. 485_497, 2015），据称该方案是安全的，可以确保 CSP 拥有合同所需的所有副本。然而，在这封信中，我们表明该方案很容易受到复制求和攻击和单副本攻击，作弊的CSP只需要投入单个副本的存储成本，同时仍然可以通过验证者的验证。随时挑战。因此，在这种情况下该方案不再安全。此外，我们提出了一些简单但有效的对策，并给出了免受上述两种攻击的修复方案。