@techreport {27459,
	title = {Blockchain for Healthcare: Opportunities, Challenges, and Future Directions},
	year = {2020},
	publisher = {Simula Research Laboratory},
	abstract = {The continuous generation of large volume of medical data from different sources, such as patient monitoring, clinical trials management, and processing payments and reimbursement claims, makes healthcare a data-intensive domain. This data needs to be shared among different medical facilities for various purposes, such as in-depth data analysis and collaborative research, to achieve innovative advances in the medical treatment procedures and drug developments, and providing personalised healthcare services to the patients. However, the existing data exchange solutions in healthcare domain exhibits several challenges, like data security, patient privacy, data owner consent management, interoperability, and chain-of-custody. Recently, the industry and research community turned its focus on the possible use of blockchain technology to solve one or more of the above challenges in healthcare domain. The blockchain technology along with the support from smart contracts is considered as an adequate solution for secure and efficient medical data sharing. It is due to its unique features, such as decentralization, trustlessness, immutability, traceability, and security. In this paper, we provide a comprehensive survey on the state-of-the-art efforts that envision the usage of blockchain-based solutions to improve one or more aspects in healthcare domain. 
To this end, first we categorize the existing works based on a set of key challenge(s) that they address in healthcare by using blockchain technology. The particular challenges that we consider for the categorization of the surveyed articles are as follows: (i) security and privacy, (ii) interoperability, (iii) compliance management, (iv) medical records management, and (v) chain-of-custody. Second, we discuss the benefits and limitations that the surveyed solutions exhibit when incorporating blockchain in healthcare. We also investigate the causal relationships among these challenges to demonstrate how various factors causing these challenges are connected with each other. Third, we identify the practical issues that blockchain-driven healthcare must overcome to become a success, and we suggest the additional future research required to address the identified issues. Our survey shows that there is an exponential increase in the number of efforts towards the use blockchain and smart contracts to improve various functionalities in several healthcare services such as clinical trials, medical data management, and drug supply chain management. However, most of these efforts are still in their initial phases, and a lot of work still remains before their integration in practical healthcare scenarios. This work is currently in-progress, and it is planned to be performed in an accepted research-based innovation project by Research Council of Norway called {\textquotedblleft}SMARTMED {\textendash} Secure and accountable sharing of medical records using smart contracts and blockchain{\textquotedblright}.},
	keywords = {blockchain, Cloud computing, Electronic Health Records, Internet of things, Medical data, security and privacy},
	author = {Lal, Chhagan and Marijan, Dusica}
}
