International Journal of Control and Automation Vol. 10, No. 11 (2017), pp.133-144 http//dx.doi.org/10.14257/ijca.2017.10.11.12 ISSN: 2005-4297 IJCA Copyright © 2017 SERSC Australia Blockchain-Based User-Centric Records Management System 1 Si-Wan Noh 1 , Youngho Park 2 , Chur Sur 3 , Sang-Uk Shin 2 and Kyung-Hyune Rhee 2 1 Interdisciplinary Program of Information Security Graduate School Pukyong National University, Republic of Korea 2 Department of IT Convergence and Application Engineering Pukyong National University, Republic of Korea 3 Department of Information Security, Busan University of Foreign Studies, Republic of Korea 1 nosiwan@pukyong.ac.kr, 2 pyhoya@pknu.ac.kr, 3 kahlil@bufs.ac.kr 2 shinsu@pknu.ac.kr, 2 khrhee@pknu.ac.kr Abstract Sharing of medical records among institutions can present certain risks to patient’s privacy. An exposure of personal medical records causes damage to the finance, etc. Sometimes, it could put patient’s life in danger. To achieve secure data sharing between institutions, many studies use cloud storage to store medical records. However, many studies suppose that cloud service providers were trustworthy. These systems required a key establishment with the cloud service providers and all the access logs are governed by cloud service providers. Patients should ask cloud service providers to check these access logs. However, it can be forged by cloud service providers during the request process. In this paper, we propose blockchain based medical records management system for secure data sharing. In order to share securely, we use proxy re-encryption scheme. Also, we use blockchain technology to audit access logs without modification. Keywords: Medical Record Management, Blockchain, Healthcare, Cloud Storage, Proxy Re-encryption 1. Introduction In the past, medical records were kept in the form of a paper document by hospitals. Hence, many patients received medical care service from their family doctor and a lot of medical records are kept by their family doctor. However, paper documents required space for storing it. Also, to retrieve a record from document box is difficult. These days, with the development of the technology, patients receive healthcare service from specialists in each field. To efficiently share medical records among specialists, electronic medical record (EMR) was proposed [1]. Traditional paper documents are converted to an electronic format with the associated information as a collection of records. These records are stored in the database and provided it only if an access request of this data is valid. When patients receive medical service at hospitals, they need several examinations (e.g. inspection result, X-ray image, etc. ) to receive medical treatment. Even though the patient had an examination just recently from the other hospital, it might lead to additional costs for the patient and the hospital. Sharing of medical records between specialists belonging to the same hospital is relatively easy to achieve. However, cross-institutional sharing of medical record is complex. To Received (July 5, 2017), Review Result (October 30, 2017), Accepted (November 6, 2017)