In medical cloud computing, a patient can remotely outsource her medical data to the cloud server. In this case, only authorized doctors are allowed to access the data since the medical data is highly sensitive. Before outsourcing, the data is commonly encrypted, where the corresponding secret key is sent to authorized doctors. However, performing searches on encrypted medical data is difficult without decryption. In this paper, we propose two Secure and Efficient Dynamic Searchable Symmetric Encryption (SEDSSE) schemes over medical cloud data. First, we utilize the secure k-Nearest Neighbor (kNN) and Attribute-Based Encryption (ABE) techniques to construct a dynamic searchable symmetric encryption scheme, which can achieve forward privacy and backward privacy simultaneously. These tow security properties are vital and very challenging in the area of dynamic searchable symmetric encryption. Then, we propose an enhanced scheme to solve the key sharing problem which widely exists in the kNN based searchable encryption scheme. Compared with existing proposals, our schemes are better in terms of storage, search and updating complexity. Extensive experiments demonstrate the efficiency of our schemes on storage overhead, index building, trapdoor generating and query.

中文翻译：

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对医疗云数据实现安全高效的动态可搜索对称加密

在医疗云计算中，患者可以远程将其医疗数据外包给云服务器。在这种情况下，由于医疗数据是高度敏感的，因此只有经过授权的医生才能访问数据。在外包之前，通常会对数据进行加密，将相应的密钥发送给授权医生。然而，在没有解密的情况下，很难对加密的医疗数据进行搜索。在本文中，我们针对医疗云数据提出了两种安全高效的动态可搜索对称加密（SEDSSE）方案。首先，我们利用安全的 k-最近邻 (kNN) 和基于属性的加密 (ABE) 技术构建动态可搜索对称加密方案，可以同时实现前向隐私和后向隐私。这两个安全属性在动态可搜索对称加密领域至关重要且极具挑战性。然后，我们提出了一种增强方案来解决基于 kNN 的可搜索加密方案中广泛存在的密钥共享问题。与现有提案相比，我们的方案在存储、搜索和更新复杂度方面更好。大量实验证明了我们的方案在存储开销、索引构建、陷门生成和查询方面的效率。