Numerous reviews of decentralized applications using Blockchain have been published in recent years. However, these have predominantly focused on how applications map to the characteristics of underlying protocols and discuss privacy only in passing. This chapter takes a more focused perspective by analyzing recently proposed prominent decentralized applications, categorizing them according to information privacy requirements. Three dimensions emerge as key differentiators: accessibility requirements (i.e., whether an application needs to be publicly accessible), hierarchicality requirements (i.e., the notion of different types of participants with fundamentally different permissions), and requirements on joint verifiability of transaction data (i.e., which subset of an application’s data model needs to be verifiable by others). Grouping applications along these dimensions, it becomes clear that use cases with closed accessibility requirements are most dominant in the market today. These use cases can establish information privacy through governance, deliberate data modeling, and role-based access management.

Since its inception, Healthcare 4.0 has empowered the integration of advanced technologies to create and improve the quality of healthcare services. The delivery of healthcare services has come a long way from physical appointments with doctors to remote health monitoring and disease prediction, surgery assistive systems. This advancement has only been possible because of the integration of cutting-edge technologies like Tele-healthcare, software-defined networking and many more, with healthcare systems. In this survey, we have targeted some of the pioneering research works that could contribute significantly to the future development of Healthcare 4.0 systems. We have identified the significant research gaps and presented the modern state-of-the-art of healthcare systems, introducing the Healthcare IoT Application and Service Stacks. We have also discussed the latest paradigm of Wireless Body Area Networks, emphasizing its significance and how it can contribute to the development of next-generation healthcare applications using emerging technologies like Machine Learning, Blockchain, Cloud Computing, Internet of things, Edge/ Fog Computing, Tele-healthcare, Big Data Analytics, Software-Defined Networking and many more. We have performed a comparative study of different architectural implementations considering their advantages, shortcomings, and quality-of-service requirements. We emphasize the importance of the different emerging technologies in detail, discussing the opportunities available and their potential to create better healthcare solutions that can provide superior service quality. Finally, we highlight the fundamental need for establishing security and privacy in future healthcare systems. Overall, this survey provides a strong outlook into the development of the future of healthcare 4.0.