Blockchain has led the trend of decentralized applications and shown great use beyond cryptocurrencies. Decentralized storage such as Storj and Sia leverages blockchain to establish an open platform for sharing economy, which provides private and reliable file-outsourcing services. However, the ubiquitous keyword search function over encrypted files is yet to be supported. To enable this function, we first apply searchable encryption techniques to the decentralized setting. But this primitive can hardly ensure the service integrity. The reason is that decentralized storage commonly faces severe threats from both clients and service peers. Service peers may return partial or incorrect results, while clients may intentionally slander the service peers to avoid payments. To address these threats, we utilize the smart contract to record the logs of encrypted search (aka evidence) on the blockchain, and devise a fair protocol to handle disputes and issue fair payments. Using a dynamic-efficient searchable encryption scheme as an instantiation, we craft a concrete scheme that preserves encrypted search capability and enforces ecosystem healthiness, so that service peers are incentivized to make real efforts and jointly guarantee service reliability. We implement our scheme in Python and Solidity, and test its search performance and transaction costs on Ethereum.

中文翻译：

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公平地在加密的分散存储中启用可靠的关键字搜索

区块链引领了去中心化应用的趋势，并在加密货币之外展现了巨大的用途。Storj、Sia等去中心化存储利用区块链建立共享经济开放平台，提供私密、可靠的文件外包服务。但是，尚不支持对加密文件的无处不在的关键字搜索功能。为了启用此功能，我们首先将可搜索加密技术应用于分散设置。但是这个原语很难保证服务的完整性。原因是去中心化存储通常面临来自客户端和服务对等方的严重威胁。服务节点可能会返回部分或不正确的结果，而客户端可能会故意诽谤服务节点以避免付款。为了应对这些威胁，我们利用智能合约在区块链上记录加密搜索（又名证据）的日志，并设计一个公平的协议来处理争议和发放公平的付款。以动态高效的可搜索加密方案为实例，我们制定了一个具体的方案，保留了加密的搜索能力并加强了生态系统的健康，从而激励服务对等点做出实际努力，共同保证服务的可靠性。我们在 Python 和 Solidity 中实现我们的方案，并在以太坊上测试其搜索性能和交易成本。我们制定了一个具体的方案，保留了加密搜索能力并加强了生态系统的健康，从而激励服务同行做出真正的努力，共同保证服务的可靠性。我们在 Python 和 Solidity 中实现我们的方案，并在以太坊上测试其搜索性能和交易成本。我们制定了一个具体的方案，保留了加密搜索能力并加强了生态系统的健康，从而激励服务同行做出真正的努力，共同保证服务的可靠性。我们在 Python 和 Solidity 中实现我们的方案，并在以太坊上测试其搜索性能和交易成本。