A blockchain-based preserving and sharing system for medical data privacy

Highlights

• Proposed a blockchain based medical data information system model.

• Designed an IoT based system to collect patient health data during surgery.

• Proposed a data sharing schema based on proxy re-encryption algorithm.

• Design a dual-channel Hyperledger Fabric architecture to ensure data security.

Abstract

With the rapid development of information and network technology, hospital information systems (HIS) has also become a hot research area. However, data could be subjected to the threat of security attacks, leakage, tampering, and forgery during medical data transmissions, data storage, and sharing based on public networks and cloud environments. The immutability, decentralization and anonymity of the blockchain provided new ways for solving the aforementioned problems. This paper proposes a complete medical information system model based on blockchain technology, to realize the goal of safe storage and sharing of medical data. A data collection system based on Internet of Things (IoT) was also developed that can simultaneously collect data from different types of non-invasive medical instruments to realize real-time collection of patient health record during surgery (SHR). This system designed an anonymous medical data sharing scheme based on cloud servers and proxy re-encryption algorithm to improve the security of private medical data sharing. The system was implemented based on the permissioned blockchain architecture Hyperledger Fabric, and a dual-channel Fabric deployment architecture and medical chaincode were designed for data management and access control. We also carried out computing overhead test, performance test and safety evaluation on the system, and the test results meet the requirements of actual medical production environment. The research work of this paper provides means for remote diagnosis and treatment, data mining and other practical applications based on the medical data on the blockchain.

Introduction

Hospital information system (HIS) is the infrastructure of modern hospitals. It plays a vital role in numerous aspects such as patient management, diagnosis and treatment decision. HIS manages the hospital with modern, scientific, and standardized means, which can effectively improve the hospital’s work efficiency and medical quality [1]. The patient’s medical data contains the patient’s historical physiological information, which has important reference value for the patient’s disease diagnosis and treatment, and daily health care [2]. Li et al. [3] summarized the common medical data types as electronic health records (EHR), electronic medical records (EMR) and personal health records (PHR). The patient’s medical data is the basis for the normal operation of the HIS, so the HIS usually collects, stores and manages various types of medical data of the patient. However, some problems exist in traditional HIS: (1) System security issues and difficulties in medical data sharing. Traditional HIS stores medical data in private or cloud servers, which exposes the system to the risk of malicious attacks, data leakage and tampering, and the possibility of losing private medical data. Besides, these systems usually operate independently in hospitals, which is difficult to meet the basic need of patients to share medical data. Some patients will share medical data through some cloud servers or applications, but cloud servers provided by third-party suppliers are semi-trusted and they may steal or tamper with user data. (2) Lack of patient surgical data. The physiological data of patients during surgery generated by medical instruments were not included in the medical data types summarized by Li et al. [3]. These patient health records during surgery (SHR) reflect the patient’s surgical process and facilitates the postoperative treatment and recovery of patients. The traditional method of manually recording SHR has the problems of limited storage and data collection inaccuracy. (3) Lack of analysis and application of medical data. The medical data in traditional HIS is solely managed by hospital and patients cannot access their own medical data at will, which prevents patients from effectively analyzing and using their own data. Most of the medical data is idle, resulting in a waste of valuable data resources. Internet of Things has been widely used in many fields [4]. Its real time and accuracy make it very suitable for medical data collection [5]. Blockchain is a distributed digital ledger based on encryption technologies [6], which is represented as a decentralized peer-to-peer network. Once data is confirmed and stored in the blockchain, it is difficult to tamper with. The immutability, decentralization and anonymity of the blockchain ensure the safe storage of medical data. The combination of IoT and blockchain technology provides a new way for solving the above problems.

Blockchain technology had been applied to various fields, and medical information system is among the main focuses at present [7], [8], [9], [10]. Kassab et al. [11] and Abu-Elezz et al. [12] have conducted research on common data protection mechanisms and analyzed the advantages of blockchain in the security protection and sharing of medical data. There have been many studies on introducing blockchain technology into electronic medical record systems, medical image systems, etc. [13], [14], [15], [16], [17]. The systems proposed in [13], [14], [15], [16], [17] only use blockchain for secure medical data storage. They focused on architectural design but lacked of system implementation details and data sharing procedures. Some researchers proposed schemas or frameworks for medical data storage based on blockchain and various cryptographic mechanisms [18], [19], [20], [21]. They designed specific system workflows to realize the sharing or access control of medical data. However, the proposed systems were implemented based on Ethereum, even normal transactions in these systems require a certain number of tokens, which is not applicable in hospital information systems. Besides, Xu et al. [22] adopted the PBFT consensus algorithm and LIU et al. [23] adopted the DPOS consensus algorithm in their systems, which were relatively complex for reaching a systematic consensus and ensure the security of the data. The systems proposed in [18], [19], [20], [21], [22], [23] have the weakness of low transaction efficiency, because traditional public blockchain architectures such as Bitcoin and Ethereum need to use high-power or relatively complex algorithms to reach a system consensus. Therefore, some researchers had adopted the more lightweight Hyperledger Fabric(HF) architecture for blockchain network implementation in their systems [24], [25], [26], [27]. They had developed smart contracts for system access control and data management but had less research on data sharing. Proxy re-encryption algorithm had been applied to different scenarios to achieve secure data sharing on semi-trusted cloud servers [28], but its application in the medical system based on blockchain was relatively insufficient. The Internet of Things technology has been applied to improve the efficiency of medical data collection generated by the medical instruments or personal health monitoring sensors [29], [30], [31], [32], [33], [34]. But the focus of these studies are on the construction of data collection system or data analysis. There is a lack of research on the secure storage and sharing of medical data. Many systems also analyzed and mined medical data and make contributions to disease prediction and medical quality improvement [35], [36], [37].

Taking into account the problems of traditional HIS and the current research status, this paper proposed a medical data information system model based on blockchain, Internet of Things, cloud storage and proxy re-encryption algorithm to realize the reliable collection, safe storage and sharing of medical data. The contributions and innovations of this work are as follows.

① A Hyperledger Fabric based medical data information system with dual channels and medical chaincode was proposed to realize the goal of safe storage, management and access control of medical data.

② An IoT based medical data system was designed to realize real-time data collection for six categories of non-invasive medical instruments, which can effectively improve the data collection efficiency of SHR.

③ A secure medical data sharing scheme based on proxy re-encryption algorithm was proposed to improve the security of medical data sharing.