# FAIDM for Medical Privacy Protection in 5G Telemedicine Systems
## 3 Proposed Scheme  
In this paper, we proposed a FAIDM for medical privacy protection in 5G telemedicine systems. The notations of the scheme are shown as Table 1. The system structure of proposed scheme includes remote server node, gateway node (\(GW_{i}\)), and constrained node (\(CN_{ij}\)). A constrained node is in a sensor layer of a proposed 5G IoT remote patient monitoring system structure and can be in devices which gather measured data, such as sensors or wearable devices that can be carried by a human. The role of these devices consists of monitoring or sensing the environment, so they collect and transmit data to gateway nodes. For example, in a healthcare application, sensors can be planted in or on a human's body in order to collect health-related data. Gateway nodes, which are SBSs/MBSs, are in the network or communication layers of the proposed 5G IoT remotepatient monitoring system structure, and it can be assumed that the gateway nodes have enough energy resources, performance processors, and memory. Gateway nodes process received data collected by the different constrained nodes and forward the to the remote server node. Remote server node is in architecture layer of proposed 5G IoT remote patient monitoring system structure and can be assumed that remote server node has no limitations of computing resource. Medical professionals in the architecture layer can continuously follow a patient's health status based on data received. Note that the interaction between communication and the architecture layer should be secure which may be guaranteed by functions in the core network, such as authentication server function (AUSF), authentication credential repository and processing function (ARPF), subscription identifier de-concealing function (SIDF), and security anchor function (SEAF) [47; 48], but secure communication between these two layers is not discussed in our scheme. The remote server node takes part in the system initialization and generating system parameters. A constrained node has to register to any legitimate gateway node for becoming legitimate. A gateway node has to register to the remote server node for becoming legitimate. When a patient wears a wearable healthcare device and goes home from hospital, the device transmits measured data through an IoT gateway (\(GW_{t}\)) at home which is in different domain from hospital. The system structure is show as Figure 2.  
The proposed scheme consists of seven phases: System initialization phase, gateway node registration phase, constrained node registration phase, mutual authentication and key agreement phase, anonymous identity distribution phase, and anonymous signature and verification phase. The notations of proposed scheme are shown in Table 1.  
Before system initialization phase, the healthcare services provider needs to apply for certificates \(\mathit{Cert}_{HCA\to 5}\) from healthcare certification authority before providing healthcare services. The healthcare certification authority should be a credible and dependent institute, such as National Health Service Business Services Authority (NHSBSA) of United Kingdom [49], European Federation Gateway Service (EFGS) of European Commission [50], American Hospital Association Certification Center (AHA-CC) of USA [51], Pharmaceuticals and Medical Devices Agency (PMDA) of Ministry of Health, Labor and Welfare, Japan [52], or Healthcare Certification Authority (HCA) of Ministry of Health and Welfare, Taiwan [53]. The certificate \(\mathit{Cert}_{HCA\to S}\) is regarded as the root certificate in the system, and only certified healthcare services provider can obtain \(\mathit{Cert}_{HCA\to S}\).