## 7 Architectural Challenges in Designing Any Smart Healthcare Application
### IoT Security in Smart Healthcare  
One of the most significant challenges in smart healthcare that IoT poses is data security. IoT devices collect health-related data from patients. These devices are not fully facilitated with security credentials and protocols. Thus, the cyber criminals can hack the healthcare system and compromise personal health information (PHI) of patients. Using the retrieved information, the hackers can create fake IDs for buying drugs or medical equipment and for selling them later [116]. In addition to this, a fraudulent insurance claim can be filed [86]. Traditional security is different from IoT security in many aspects. IoT, as far as built-in security, only has lightweight algorithms for resource-constrained devices, leaving privacy issues open. IoT is a heterogeneous environment with a large attack surface, few security measures, and IoT devices located in open environments. These IoT features make the ecosystem vulnerable to attacks [117]. Data confidentiality, data integrity, and data availability are the three primary security goals of any IoT implementation. Standard IoT security mechanisms are data encryption and access control for ensuring confidentiality and data integrity algorithms for ensuring integrity, firewalls, ids, and redundancy methods for ensuring availability (CIA triad). IoT security is the major challenge due to its heterogeneity features, massive communication volume, and simple authentication or access control of physical devices [118; 119]. Figure 17 depicts the possible attacks and respective security solutions of IWF layers. The Mirai botnet attack happened in 2016, a self-propagating worm targeting IoT devices that ran Linux. There are many variants of Mirai botnets that lead to distributed denial of service attacks by turning all devices into bots that are part of the network. IZIH9, Ex0, Ares, LZRD, and Miori are the major variants of Mirai that target Ethereum mining clients and Linux servers running vulnerable versions of Hadoop YARN. Much research is carried out in IoT security countermeasures for various attacks that are possible in each layer of the IWF Architecture [120]. The possible attacks and respective solutions are provided in [117] for three-layered architectures of IoT, including the perception layer, network layer, and application layer. Figure 13. presents the possible attacks and possible security solutions at each layer of the IWF Architecture. The IoT protocols are mainly classified in these layers only. IEEE 802.15.4, BLE, Wi-Fi, and LTE are perception layer protocols that use the AES-CCM algorithm; black network solutions; WEP, VPA, and WPA2 protocols; EEA; and EIA security solutions. IPv4 or IPv6, 6 LoWPAN, and RPL are network layers and transport protocols that use IPSec protocols, SEND protocols of IPv6, the Compressed IPSec protocol, Compressed DTLS, 802.15.4 security features, the SVELTE IDS solution, and AES-CCM algorithms as their security solutions. MQTT and CoAP are the most used application layer protocols and use the DTLS protocol (PSK, RPK, certificates) and Lithe solution as the countermeasures of attacks [117]. IoT security through an emerging paradigm called software-defined networking (SDN) is presented in [121]. A central program called the \"SDN controller\" takes overall network control. This promising technology improves network performance by providing security solutions for existing challenges, including DoS attack, RFID spoofing, and sinkhole attacks. IoT Authentication is the major part of IoT security described in the subsection below. IoT Authentication in Smart Healthcare  
Smart healthcare systems require robust authentication for the patient's health information. A three-factor authentication scheme is mostly used for authenticating the  
Figure 17: Possible attacks and respective security solutions of IWF layers. users of healthcare applications. The users can be both patients and doctors [119].