The widespread adoption of cloud infrastructures has revolutionised data storage and access. However, it has also raised concerns regarding the privacy of sensitive data stored in the cloud. To address these concerns, encryption techniques have been widely used. However, traditional encryption schemes limit the efficient search and retrieval of encrypted data. To tackle this challenge, innovative approaches have emerged, such as the utilisation of Homomorphic Encryption (HE) in Searchable Encryption (SE) schemes. This paper provides a comprehensive analysis of the advancements in HE-based privacy-preserving techniques, focusing on their application in SE. The main contributions of this work include the identification and classification of existing SE schemes that utilize HE, a comprehensive analysis of the types of HE used in SE, an examination of how HE shapes the search process structure and enables additional functionalities, and the identification of promising directions for future research in HE-based SE. The findings reveal the increasing usage of HE in SE schemes, particularly Partially Homomorphic Encryption. The analysis also highlights the prevalence of index-based SE schemes using HE, the support for ranked search and multi-keyword queries, and the need for further exploration in functionalities such as verifiability and the ability to authorise and revoke users. Future research directions include exploring the usage of other encryption schemes alongside HE, addressing omissions in functionalities like fuzzy keyword search, and leveraging recent advancements in Fully Homomorphic Encryption schemes.

翻译：云基础设施的广泛采用彻底改变了数据存储和访问方式。然而，这也引发了对云端存储敏感数据隐私的担忧。为解决这些问题，加密技术被广泛使用。但传统加密方案限制了加密数据的高效搜索与检索。为应对这一挑战，创新方法应运而生，例如在可搜索加密（SE）方案中利用同态加密（HE）。本文全面分析了基于HE的隐私保护技术的进展，重点关注其在SE中的应用。主要贡献包括：识别并分类现有利用HE的SE方案；全面分析SE中使用的HE类型；探讨HE如何塑造搜索过程结构并实现附加功能；以及指出基于HE的SE未来研究方向。研究结果揭示了HE在SE方案中日益广泛的应用，尤其是部分同态加密。分析还强调了索引型SE方案中HE的普遍性、对排序搜索和多关键词查询的支持，以及在可验证性、用户授权与撤销等功能方面需要进一步探索。未来研究方向包括：探索将HE与其他加密方案结合使用，解决模糊关键词搜索等功能缺失问题，以及利用全同态加密方案的最新进展。