Security Optimization of Resource-Constrained Internet of Healthcare Things (IoHT) Devices Using Lightweight Cryptography

Introduction

The Internet of Things has become the most widely used term in the world today. It is a technical concept that entails practical devices such as sensors and actuators that are used to collect real-time data, convey that data over the internet, and store that data on cloud-based platforms with or without human participation (Gubbi et al., 2013; Singh, Sharma, & Moon, 2017; Thakor et al., 2021). In 1999, Kevin Ashton coined the term “Internet of Things” to promote the usage of radio frequency-based identification (RFID), which involves a variety of embedded devices. With the advent of home automation, industrial energy meters, wearable and self-health care devices in 2011, the tremendous expansion of IoT-based devices began (Tawalbeh et al., 2020). Health care is an important sector that is one of the major contributors to the total number of IoT enabled devices in the world. The invention of IoHT enables patients to self-assess their body conditions and also simultaneously upload these data to the hospital’s server so that doctors can keep track of patients’ health condition and call for checkups and visits only when required which ultimately helps in saving money as well as time (Engineering, 2017; Fuzon, 2019). However, the massive outbreak of this technology has led to many issues and challenges regarding the security of patient’s data.

Data protection is required at three layers in any IoHT device: physical/design, communication, and computation. (McKay et al., 2017) They are further divided into resource-rich (phones, tablets, laptops) and resource-constrained (sensors, RFID) devices. Devices with limited resources are frequently utilized to handle real-time applications that demand precise data processing. Furthermore, they are constrained in terms of power consumption, memory, and processing rates (Biryukov & Perrin, 2017; Toshihiko, 2017). The focus of this research is on the implementation of algorithms for device security in the latter group.

Figure 1.

Categorization of IoT devices

In most of the countries, the authentic information provided by the healthcare data should be confined through “Health Information and Portability Accountability Association (HIPAA)” (Ullah et al., 2018). Efficient and safe implementation of these healthcare systems can be achieved by using optimized and robust security systems (Butpheng et al., 2020). Cryptography is the widely applied technique to secure the data and prevent the leakage of information. An IoHT device begins at the implementation of physical layer using sensors, RFID tags, actuators etc. to acquire the information regarding patient’s health. Typical encryption algorithms like AES, DES, RSA cannot be applied to these embedded devices as they are more suitable for devices with high computation powers. Lightweight cryptographic (LWC) techniques are utilized in such fields.

As the term suggests they are capable of operating at lower power, smaller memory and better computation speeds (McKay et al., 2017). The most commonly used LWC methods in the field of healthcare are PRESENT, CLEFIA, PICOLO, KATAN, SPECK and SIMON. These ciphers are most widely used in IoHT devices as they are more advantageous in both software as well as hardware application. The function of any cryptography is to convert any plain text to corresponding cipher text using secret keys, logical shifting operations and permutation levels and then convert the cipher text back into plain text. Block ciphers are given more importance in cryptographic fields as they are more efficient and versatile in choosing the information including the key size (Chaudhury et al., 2017; El-hajj et al., 2017).