Blockchain - based IoT: A Survey

Blockchain and Internet of Things (IoT), two of the top disruptive technologies, are already on their way of reshaping our future of the digital world, characterized by a drastic change in the current network architecture. Incorporation of IoT has brought the objects around us to life, making them 'smart' and capable of communicating with each other, thereby amassing massive data by constantly capturing the physical world, for analyzing and performing some intelligent action based on the same. It has made possible our dream of seamless integration of the digital and physical worlds, changing the very essence of our perception of the physical world. But, the problem with current IoT solutions is its need for a centralized party (like a cloud server), for connecting and communicating via the Internet, which poses a great threat to the privacy and security of the vast sensitive data being generated, whereas the original architecture design demands for a decentralized one like distributed or peer -to- peer (P2P) system. So, blockchain comes into play, providing a secure and trustworthy way of sharing information using a distributed/P2P model, to achieve transparency, security, privacy, auditability, resilience, access authentication, data immutability, etc. In this paper, we will look into how to combine both the technologies to overcome their shortcomings and obtain a greater gain from their benefits. We have presented a comprehensive survey on the basics of both the technologies, and the blockchain-based IoT (BIoT) architecture, protocols and functioning, and few examples BIoT applications that can be built on top of it, and comparison. (C) 2019 The Authors. Published by Elsevier B.V.