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S. Bhattacharyya et al.

Keywords Blockchain · Internet of Things (IoT) · BCoT · Industry 4.0

1

Introduction

Prolific digitization associated with the advent of the Internet of Things (IoT) has

revolutionized a paradigm shift in the industrial and manufacturing sector coined by

the term “Internet of Things (IoT)”. The Industry 4.0 standard incorporates the power

of smart technology, real-time data analysis and smart infrastructures, cyber-physical

systems, and intelligent cognitive computing in a cloud environment to analyze the

explosion in data produced and consumed. IoT promotes multi-disciplinary busi-

ness intelligence and supports well-organized quality management and perceptible

supply chains coupled with prognostic maintenance, improved field services, asset

tracking, and imperishable green practices. As such, an IoT ecosystem is meant

for effective control of numerous physical and virtual smart devices interconnected

together and distributed across the entire physical world to enable collection and

secured exchange and analysis of the massive amount of ambient data. The advent of

cloud computing has provided a wide range of possibilities for efficiently handling

distributed computing. However, it calls for the provisioning of high-configuration

servers and high-speed networks for augmenting storage and computation-intensive

services. In order to address this problem, IoT services have envisaged a centralized

cloud-enabled IoT framework modeled as a black box facilitating the emergence of a

resilient, adaptable, fault-tolerant, trusted, and secure service architecture that lever-

ages reduced maintenance costs and time-critical application support. Blockchain

technology stands out to be one of the most suitable candidates for enabling a secure

and distributed IoT ecosystem, thereby adding a helping hand in countering these

inherent challenges and issues. Blockchain technology is a conglomerate of cryp-

tography, public key infrastructure, and economic modeling to induce distributed

database synchronization in peer-to-peer networking supported by a decentralized

consensus. The underlying features of distributed architecture, immutability, veri-

fiability, and fault-resilience make it suitable for envisaging a decentralized IoT

infrastructure, thereby giving rise to a Blockchain for Internet of Things (BCoT) [1–

5]. Different industry-based solutions and platforms including Lola [6], COSMOS

[7], Dajie [8], Filament [9], Slock.it [10], Smart Axiom [11], BlockVerify [12],

Xage Security [13], Ubirch [14], Multichain [15], ShoCard [16], Chronicled [17],

Uniquid [18], Riddle and Code [19], Datum [20] have been introduced to cater

public, private, and federated blockchains with the goal of addressing confidentiality

and integrity, monetization, reliability, trust, identity, and data management issues.

However, numerous operational and technical challenges are to be conquered to

achieve an absolute IIoT decentralization using blockchain due to the wide spec-

trum of the IoT applications including the food industry, e-voting, real estate, cyber-

security, healthcare services, supply chain and logistics, music, insurance, energy and

smart grid management, and apparel industry, to name a few. Apart from the technical

challenges out of processing, storage, communications, and availability, associated