基于区块链的电子医疗病历可控共享模型

电子医疗病历共享能够提高医疗诊断的准确性, 促进公共医疗领域的发展. 针对目前普遍存在的不同医院之间病历共享困难、病人无法掌握其病历的使用情况等问题, 本文提出了病人可控、云链协同的病历共享模型. 各级医院组成联盟区块链, 病历数据实行链上、链下混合存储. 病历共享模型利用聚类算法, 改进实用拜占庭共识算法, 使得各节点可以更高效地达成共识. 将基于属性的加密方案与多关键词加密方案结合进行病历加密, 实现了数据可控共享, 病人可自主定义访问策略, 同时用户可以对加密病历进行安全、精确检索. 考虑到用户属性的动态更新, 本文设计了属性更新子协议. 最后评估了模型的安全性和性能, 并分析了模型的优劣势.

A Controllable Sharing Model for Electronic Health Records Based on Blockchain

Sharing electronic health records among medical institutions can help improve the accuracy of medical diagnosis and promote the development of public medical field. In practice, however, it is difficult to share health records among hospitals, and patients typically have no knowledge about the usage of their health records. In order to solve these problems, this paper proposes a patient-controllable sharing model for health records based on a collaborating cloud-blockchain architecture, in which hospitals form a consortium blockchain, and data can be stored in both on-chain and off-chain fashions. The cluster algorithm is used to improve the practical Byzantine fault tolerance algorithm, so that nodes can reach consensus more efficiently. In order to fulfill the controllability, we propose to use the attribute-based encryption scheme and multi-keyword encryption scheme to encrypt health records, so that patients can define their access policies, and users can safely and accurately retrieve the encrypted health records. Considering the dynamic updating of user properties, we design an attribute updating sub-protocol. Finally, we evaluate the security and performance of our model, and also analyze its advantages and disadvantages.