报告题目：Efficient and Privacy-Preserving Similarity Query with Access Control in eHealthcare
郑艳冬，西安电子科技大学网络与信息安全学院副教授，2022年博士毕业于加拿大新布伦瑞克大学，导师IEEE Fellow Rongxing Lu教授，研究方向是应用密码学、数据安全与隐私保护。近5年，在国际期刊和会议发表论文60余篇，其中以第一作者身份发表论文23篇，包括IEEE TIFS, IEEE TDSC, IEEE TSC等CCF A类论文11篇（含高被引论文1篇）、中科院一区论文3篇，主持国家重点研发计划子课题、陕西省秦创原高层次创新创业人才、陕西省科学基础研究计划等多项国家级和省部级项目，曾获国家优秀留学生奖、中国中文信息学会科学技术奖-“钱伟长中文信息处理科学技术奖”一等奖等多项荣誉。
Similarity queries, giving a way to disease diagnosis based on similar patients, have wide applications in eHealthcare and are essentially demanded to be processed under fine-grained access policies due to the high sensitivity of healthcare data. One efficient and flexible way to implement such queries is to outsource healthcare data and the corresponding query services to a powerful cloud. Nevertheless, considering data privacy, healthcare data are usually outsourced in an encrypted form and required to be accessed in a privacy-preserving way. In the past years, many schemes have been proposed for privacy-preserving similarity queries. However, none of them is applicable to achieve data access control and access pattern privacy preservation. Aiming at this challenge, we propose an efficient and access pattern privacy-preserving similarity range query scheme with access control (named EPSim-AC). In our proposed scheme, we first design a novel tree structure, called k-d-PB tree, to index healthcare data and introduce an efficient k-d-PB tree based similarity query algorithm with access control. Second, to balance the search efficiency and access pattern privacy of k-d-PB tree, we also define a weakened access pattern privacy, called k-d-PB tree’s β-access pattern unlinkability. After that, we preserve the privacy of k-d-PB tree based similarity queries with access control through a symmetric homomorphic encryption scheme and present our detailed EPSim-AC scheme. Finally, we analyze the security of our scheme and also conduct extensive experiments to evaluate its performance. The results demonstrate that our scheme can guarantee k-d-PB tree’s β-access pattern unlinkability and has high efficiency.