Received: 2 February 2019 Revised: 27 April 2019 Accepted: 16 May 2019 DOI: 10.1002/spy2.83 SURVEY PAPER Review on “Blockchain technology based medical healthcare system with privacy issues” Arijit Saha Ruhul Amin Sourav Kunal Satyanarayana Vollala Sanjeev K. Dwivedi Computer Science & Engineering, DR SPM International Institute of Information Technology, Chattisgarh, India Correspondence Ruhul Amin, Computer Science & Engineering, DR SPM International Institute of Information Technology, Chattisgarh, India. Email: amin_ruhul@live.com Healthcare has been the industry with the highest boom in terms of both revenue and data. With so much of electronic health records, the security has been the need of the hour. To make this critical information more secure, there has been an urge to use the blockchain technology. Therefore, researches came up with a solution of blockchain technology in medical healthcare that will not only protect data from being tampered but will also ensure that the data leakage is stopped. This technol- ogy could preserve data and thus guarantee reliability. And if this technology is used along with cloud computing technology, problems related to storage can also be van- ished, because cloud is trusted for storing and managing data. Also, the blockchain can address the security issues of the cloud. Indeed, medical data sharing and stor- ing with Blockchain-based cloud can address a lot of issues of medical data. The main aim of this paper is to present the current state-of-the-art on blockchain-based medical healthcare system. We have clearly discussed several existing works on the same domain and also presented a comparative study among the published works. KEYWORDS architecture, blockchain, healthcare system, security 1 INTRODUCTION Medical care has been an indispensable part of our lives and so the medical data, for example, prescriptions, previous medical records has also become a vital part for patient's diagnosis and for further proceedings. Traditionally, medical data were recorded on paper, which were prone to get damaged and modified. Therefore, it was necessary to preserve the data electronically. However, the medical database could be tampered or deleted permanently. Then, there was also a concern on information blocking. Information blocking occurs when an entity, for example, a person may be with or without his intention to access the data which should not have been seen without the patient's or hospital's concern. 1 Technology always plays a very significant role if it is about enhancing the quality or about resolving issues such as resource allocation along with information blocking, here in medical-care data sharing technology needed to be evolved with time. Generally, patients may have a lot of service providers in terms of medical healthcare that include general physicians or specialists or even therapists. Since a disease could be because of the previous disease, 2 so they all need to share health record securely without any manipulation. Patient need not be always a professional or to have a good memory to remember all the data properly if all the data are stored and shared securely. Patients need to keep updating their own medical data history. According to the Fundamental Right to Life and Liberty under Article 21 and freedom of expression and movement under Articles 19(1)(a) and (b) of the Constitution of India, a patient has right to consult or get transferred to another hospital for his treatment. Now, again it is patients' wish to share his data. Also, if a hospital wants to share his data for research there must be consent from the patient. Again, if consent is also there then the data transferring process takes a lot of time. Moreover, if the data that are transferred are in paper mode or even through Security Privacy. 2019;e83. wileyonlinelibrary.com/journal/spy2 © 2019 John Wiley & Sons, Ltd. 1 of 14 https://doi.org/10.1002/spy2.83