I. Introduction
The speed with which blockchain technology has moved from theoretical belief to practical reality is remarkable. Blockchain technology is transforming various industries, from healthcare to the food supply. In the era of Healthcare 4.0, millions of healthcare-based IoT devices must quickly link and communicate data, and these data exchanges must be shareable and transparent [1]. Blockchain is a decentralized system that restricts data changes and allows secure, private, and instant transactions. Patients, doctors, pathologists, insurance companies, and hospitals have all thought about how healthcare can improve healthcare services, user satisfaction, record keeping, and overall customer experience [2]. The maturity of block chain technology and the growing need for digital identities in healthcare is under research. This includes patient health data, identity management, insurance management, storage, data transfer, and service information. Smart contracts and blockchain technology will store this data in a public ledger. The data in this public ledger can only be accessed by those entitled to do so. Individuals will be able to authenticate and use certificates in real time due to the requirements of health organizations [3].