An Effective Blockchain Based Secure Searchable Encryption System Aitizaz Ali 1 , Mehedi Masud 2 , Ateeq ur Rehman 3 , Can Chen 1 , Mehmood 4 , Mohammad A. AlZain 5 and Jehad Ali 6,* 1 School of IT, Monash University, Subang Jaya, Sunway, Malaysia 2 Department of Computer Science, College of Computers and Information Technology, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia 3 Department of Biomedical Engineering, Foundation University, Islamabad, Pakistan 4 Department of IT, University of Haripur, Haripur, KPK, Pakistan 5 Department of Information Technology, College of Computers and Information Technology, Taif University, Taif, 21944, Saudi Arabia 6 Department of Computer Engineering and Department of AI Convergence Network, Ajou University, Suwon, 16499, Korea *Corresponding Author: Jehad Ali. Email: jehadali@ajou.ac.kr Received: 27 September 2021; Accepted: 01 December 2021 Abstract: Security of Patient health records (PHR) is the most important aspect of cryptography over the Internet due to its value and importance preferably in the medical Internet of Things (IoT). Search keywords access mechanism is one of the common approaches which is used to access PHR from database, but it is sus- ceptible to various security vulnerabilities. Although Blockchain-enabled healthcare systems provide security, but it may lead to some loopholes in the existing schemes. However, these methods primarily focused on data storage, and blockchain is used as a database. In this paper, Blockchain as a distributed database is proposed with homomorphic encryption technique to ensure a secure search and keywords-based access to the database. Moreover, the proposed approach provides a secure key revo- cation mechanism and update various policies accordingly. A secure patient health- care data access scheme is devised, which integrates blockchain and trust chain to fulfill the efficiency and security issues in the current schemes for sharing both types of digital healthcare data. Our proposed approach provides improved security, effi- ciency, and transparency with cost effectiveness. We performed our simulations based on the blockchain based tool termed as the Hyperledger fabric and Origionlab for analysis and evaluation. We have compared our proposed results with the bench- mark models. Our comparative analysis justify that our proposed framework gives improvement in security and searchable mechanism for healthcare system. Keywords: Blockchain; security; energy optimization; encryption; homomorphic encryption; secure searchable encryption 1 Introduction Patient health record system (PHR) is the significant and vital information related to a patient history and his/her details. Digital healthcare system is considered as the platform for transferring and receiving patient This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Intelligent Automation & Soft Computing DOI:10.32604/iasc.2022.023930 Article ech T Press Science