With the rapid development of cloud computing, vast amounts of duplicated data are being uploaded to the cloud, wasting storage resources. Deduplication (dedup) is an efficient solution to save storage costs of cloud storage providers (CSPs) by storing only one copy of the uploaded data. However, cloud users do not benefit directly from dedup and may be reluctant to dedup their data. To motivate the cloud users towards dedup, CSPs offer incentives on storage fees. The problems with the existing dedup schemes are that they do not consider: (1) correctness - the incentive offered to a cloud user should be computed correctly without any prejudice. (2) fairness - the cloud user receives the file link and access rights of the uploaded data if and only if the CSP receives the storage fee. Meeting these requirements without a trusted party is non-trivial, and most of the existing dedup schemes do not apply. Another drawback is that most of the existing schemes emphasize incentives to cloud users but failed to provide a reliable incentive mechanism. As public Blockchain networks emulate the properties of trusted parties, in this paper, we propose a new Blockchain-based dedup scheme to meet the above requirements. In our scheme, a smart contract computes the incentives on storage fee, and the fairness rules are encoded into the smart contract for facilitating fair payments between the CSPs and cloud users. We prove the correctness and fairness of the proposed scheme. We also design a new incentive mechanism and show that the scheme is individually rational and incentive compatible. Furthermore, we conduct experiments by implementing the designed smart contract on Ethereum local Blockchain network and list the transactional and financial costs of interacting with the designed smart contract.

翻译：随着云计算的快速发展，大量重复数据被上传至云端，造成存储资源浪费。数据去重（dedup）是一种高效解决方案，通过仅存储上传数据的一个副本，可节省云存储提供商（CSP）的存储成本。然而，云用户无法直接从去重中获益，可能不愿对其数据执行去重操作。为激励云用户参与去重，CSP会提供存储费用优惠。现有去重方案存在以下问题：（1）正确性——提供给云用户的激励应精确计算且无偏袒；（2）公平性——当且仅当CSP收到存储费用时，云用户才能获得上传数据的文件链接和访问权限。在无可信第三方的情况下实现这些要求具有挑战性，现有去重方案大多无法适用。另一缺陷是现有方案虽强调对云用户的激励，却未能提供可靠的激励机制。由于公共区块链网络具备可信第三方的特性，本文提出一种新型基于区块链的去重方案以满足上述要求。该方案中，智能合约负责计算存储费用激励，并将公平规则编码至智能合约中，以促进CSP与云用户之间的公平支付。我们证明了所提方案的正确性与公平性，同时设计了一种新型激励机制，验证了方案满足个体理性与激励相容性。此外，我们在以太坊本地区块链网络上部署所设计的智能合约进行实验，列出了与智能合约交互的交易成本与财务成本。