# A Hyperledger Fabric-Based System Framework for Healthcare Data Management
## 4 System Design and Implementation
### System Entities and Users  
Healthcare data. The healthcare information in current medical practices includes the data that is related to a person's medical history, such as electronic health record (EHR), lab results, X-rays, clinical information, prescription history, and notes. In the proposed system, the definition and types of healthcare information are exactly the same as the existing medical practices, which reduces the difficulty of system conversion and upgrade. Figure 1: System functions in the proposed framework. Figure 2: Organizations, clients, and peers in Fabric network. In sub-section on implementations, the type of medical data will be limited to test result, diagnosis, and treatment for simplification. Patient. Traditionally, during diagnosis and treatment, patients usually get immediate feedback on their medical records and need to keep them properly for the subsequent treatment. After treatment, patients have little idea about how their healthcare information is used by the clinic or doctor which has caused many privacy concerns. Under the new scheme, one of the most important functions is to open the access interface for patients themselves, as well as track the usage of data. Since the system would allow patients to completely save all medical records, as well as classify, highlight, and review their healthcare information. On the other hand, user privacy concerns are resolved by allowing patients to track the usage of their healthcare information and identify any illegal access. Each record is attached by the visitor's address, identity, organization information, and access time. Once patients discover illegal access, data usage can be used as evidence to help users protect their rights through legal means. Medical service provider. Doctors still have the obligation to collect, record, and save medical information, as well as the need to share and forward specific data with other medical service providers. The security of healthcare information in the system not only depends on the doctors' professionalism but also can be supervised by the patients' level of consents. Additionally, the new scheme provides them with a more convenient data management solution by connecting existing different platforms so that data can be shared among different medical institutions without increasing costs. A basic level of consent is that, when the patient authorizes the doctor to provide medical services to them, the doctor obtains permission to reasonably use the patient's healthcare information. Data processing centre. The virtual logical data processing centre will work as nodes in the blockchain for maintaining the ledger and smart contracts. All applications need to be connected to one of the nodes to achieve the functions of calling data. Its specific work content will be shown in the following implementation part. Blockchain network. The blockchain network is based on Hyperledger Fabric, which supports a permissioned network where all participants must be authorized. Through the channel, the healthcare data management system achieves the isolation of different services in the blockchain network according to the needs of users, such as clinics and insurance companies. Channels can also be privatized and contain only a specific set of participants. The public key is used to generate encryption certificates that are bound to organizations, institutions, patients, and medical staff. Therefore, setting permission for participants, channels, and access control help to address privacy and confidentiality concerns effectively. Moreover, the storage and sharing of data assets can be achieved through the blockchain; healthcare information is such a data asset, but has not been widely developed. The blockchain also helps to confirm the share of ownership of healthcare data. Medical cloud. The original healthcare data is fragmented, stored in the cloud, and linked via the blockchain, whereas the usage record of the original data is stored on the blockchain.