【摘要】 针对数据要素在生命周期使用过程中面临的安全检索问题，以能够准确描述多种数据类型的长文本为研究对象，聚焦对称加密场景下的长文本安全检索需求，围绕长文本密文搜索的问题建模、算法设计与安全模型构建等方面展开研究，设计了一种面向长文本的对称可搜索加密方案.针对长文本数据字符规模大、字符空间固定和位置特征显著等特点，提出了粒子化搜索思想，并构建了相应的实例化位图索引结构，进而设计出支持任意通配符的长文本密文搜索方案.该方案在基于模拟的框架下被证明满足L-适应性安全.为进一步评估方案的实际效率，首先在理论上与多个现有方案在存储、计算和通信开销方面进行了对比分析，证明了所提方案在理论上的高效性，进一步地，通过实验将所提方案与明文基线方案进行性能对比.结果表明，所提方案的索引构建时间约为基线方案的100倍，而搜索时间与基线方案处于同一量级，验证了方案在搜索阶段的实用性与高效性.更多还原

【Abstract】 Addressing the secure retrieval challenges faced by data elements throughout their lifecycle, this paper focuses on long-text data capable of accurately describing diverse data types.To meet the requirements for secure long-text retrieval in symmetric encryption scenarios, we conduct research on problem modeling, algorithm design, and security model construction for ciphertext search over long texts and propose a symmetric searchable encryption scheme tailored for long-text data.To accommodate the characteristics of long-text data—such as large character volume, fixed character space, and significant positional features—we introduce the concept of granular search and construct a corresponding instantiated bitmap index structure.This enables the design of a ciphertext search scheme supporting arbitrary wildcards.The proposed scheme is proven to satisfy L-adaptive security under a simulation-based framework.To evaluate the practical efficiency of the scheme, we first conduct a theoretical comparison with several existing schemes in terms of storage, computation, and communication overhead, demonstrating the theoretical efficiency of our approach.Furthermore, experimental comparisons are performed between the proposed scheme and a plaintext baseline.Results show that the index construction time of our scheme is approximately 100 times that of the baseline, while the search time remains within the same order of magnitude, validating the practicality and efficiency of the scheme during the search phase.更多还原