Blockchain-Based Smart and Secure Healthcare System Sheikh Mohammad Idrees , Iflah Aijaz , Parul Agarwal , and Roshan Jameel Abstract The healthcare data today is scrappy and not stored properly at a single location. However, some of the records are not even made digital that leads to diffi- dent researches. The number of substandard medicines in the market is increasing, so is the deceitful insurance claims. Moreover, the patient-centric models are in high demand, because the patients are becoming more aware of all the aspects and requesting an infrastructure that gives most of the controls to patients themselves. Such systems would reduce the need for intermediaries, and also keep the confiden- tiality and anonymity of the patient data intact. The desired framework is supposed to safely handle the Electronic Health Records (EHRs), insurance claims and regula- tory policies, promote researches and medicinal discoveries, etc. The healthcare data is big and heterogeneous that is usually stored in the cloud environment. However, the number of attackers on the cloud is increasing; therefore, a framework is required where the data privacy is maintained. In this chapter, a smart healthcare system based on blockchain technology is discussed, which would have the ability to provide real- time data access in a transparent, traceable, and trustful manner. The blockchain has transformed several industries including finance, manufacturing, e-commerce, education, etc. and is making its way into the healthcare industry as well. The blockchain is a distributed technology based on peer-to-peer decentralized network, which does not have any central authority controlling the system. The data within the blockchain network is represented in the forms of blocks. Cryptographic algorithms S. M. Idrees Department of Computer Science (IDI), Norwegian University of Science and Technology (NTNU), 2815 Gjøvik, Norway e-mail: sheikh.idrees99@gmail.com I. Aijaz · P. Agarwal (B ) · R. Jameel Department of Computer Science and Engineering, Jamia Hamdard, New Delhi 110062, India e-mail: pagarwal@jamiahamdard.ac.in I. Aijaz e-mail: iflah.iflah1@gmail.com R. Jameel e-mail: roshijameel@gmail.com © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 R. Agrawal and N. Gupta (eds.), Transforming Cybersecurity Solutions Using Blockchain, Blockchain Technologies, https://doi.org/10.1007/978-981-33-6858-3_9 165