With the emergence of cloud storage security, how to ensure the security of cloud storage has become a research focus. The typical searchable encryption model consists of a single cloud service provider and has some unsolvable drawbacks. In this article, a new searchable encryption scheme in multi-cloud was proposed based on blockchain. We first define a system model in multiple clouds and combine multiple cloud service providers to store data through a consortium chain. Then we store the encrypted documents and indexes in The Interplanetary File System (IPFS) and store the hash value and IPFS address of the documents in the blockchain. Our scheme can provide outsourced encrypted data retrieval based on multiple keywords, as well as verification schemes for the integrity of retrieved files. The theoretical analysis and experiments on real-world data show the security and high performance of our scheme.

中文翻译：

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使用双层区块链的多云存储的可搜索加密方案

随着云存储安全的出现，如何保证云存储的安全成为研究热点。典型的可搜索加密模型由单个云服务提供商组成，并具有一些无法解决的缺陷。本文提出了一种基于区块链的多云可搜索加密新方案。我们首先在多个云中定义一个系统模型，并结合多个云服务提供商通过联盟链存储数据。然后我们将加密的文档和索引存储在星际文件系统（IPFS）中，并将文档的哈希值和 IPFS 地址存储在区块链中。我们的方案可以提供基于多个关键字的外包加密数据检索，以及检索文件完整性的验证方案。