【摘要】 为实现云端电子病历的安全访问并提升医生诊断的效率，针对云存储的医疗数据，提出一种支持更新的多关键字排名可搜索加密方案。结合TF-IDF权重统计方法和安全kNN加密技术实现用户的多关键字排名检索，可查询Top-k最相关的病历；通过K-Means和后续遍历算法构建一种新的平衡索引树并制定相应的搜索策略，提高查询效率；在此基础上，利用相关路径更新的策略，实现数据库增、删、改的动态操作。通过理论分析和实验验证，证明方案的安全性和有效性。更多还原

【Abstract】 To achieve secure access to cloud based electronic medical records and improve the efficiency of doctor diagnosis, a multi keyword ranking searchable encryption scheme supporting update was proposed for medical data stored in the cloud. Combined with TF-IDF weight statistics method and secure kNN encryption technology, multi-keyword ranking retrieval of users was implemented to query the Top-k most relevant records. A new balanced index tree was constructed using K-Means and subsequent traversal algorithms, and corresponding search strategy was formulated to improve search efficiency. On this basis, the dynamic operation of adding, deleting and modifying database was realized by using the strategy of correlation path updating. Theoretical analysis and experimental verification show the security and effectiveness of the scheme.更多还原