VKSE-MO: verifiable keyword search over encrypted data in multi-owner settings

Searchable encryption (SE) techniques allow cloud clients to easily store data and search encrypted data in a privacy-preserving manner, where most of SE schemes treat the cloud server as honest-but-curious. However, in practice, the cloud server is a semi-honest-but-curious third-party, which only executes a fraction of search operations and returns a fraction of false search results to save its computational and bandwidth resources. Thus, it is important to provide a results verification method to guarantee the correctness of the search results. Existing SE schemes allow multiple data owners to upload different records to the cloud server, but these schemes have very high computational and storage overheads when applied in a different but more practical setting where each record is co-owned by multiple data owners. To address this problem, we develop a verifiable keyword search over encrypted data in multi-owner settings (VKSE-MO) scheme by exploiting the multisignatures technique. Thus, our scheme only requires a single index for each record and data users are assured of the correctness of the search results in challenging settings. Our formal security analysis proved that the VKSE-MO scheme is secure against a chosen-keyword attack under a random oracle model. In addition, our empirical study using a real-world dataset demonstrated the efficiency and feasibility of the proposed scheme in practice.摘要创新点可搜索加密是一种具有隐私保护的技术, 它允许云租户执行密文数据的存储和检索, 且在大部分的可搜索加密方案中, 云服务器被假定为是诚实但好奇的。但是, 在实际应用场景中, 云服务器是一个半诚实但好奇的第三方实体, 其可能为了节省计算和带宽资源而恶意地执行一部分搜索操作并返回一部分不正确的搜索结果。因此, 提供一种方法来确保搜索结果的正确性显得极其重要。已有的可搜索加密方案允许多个数据拥有者分别上传不同的文档到云服务器, 但是这些方案被应用到一个不同的实际应用场景中将会带来巨大的通信和存储开销, 即一个文档被多个数据拥有者共享。为此, 我们利用多重签名技术提出了支持挑战型的多数据拥有者场景的可验证密文检索方案, 所提方案仅需为同一个文档构建一个索引值, 同时能确保搜索结果的正确性。严格的安全分析表明文中方案在随机预言模型中是抵抗关键字选择攻击的。此外, 基于实际数据集的实验结果表明文中方案在实际应用场景中是高效的、可行的。