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the Bitcoin model to prove its efficiency in Sect. 8. In Sect. 9, the future research

directions are mentioned and finally, Sect. 10 concludes the work and the references

used are documented.

3

Background and Related Work

Blockchain is an auditable, immutable, time-stamped distributed ledger of blocks.

It securely stores the details of every transaction performed in the network. The

immutable ledger technology uses a peer-to-peer network in order to maintain secu-

rity and anonymity [13]. Each participating node present in the blockchain network

preserves a complete copy of the ledger. These ledgers update continuously, on the

validation of each transaction [13]. Initially, blockchain was proposed for executing

online exchanges using digital currency. The first proof-of-work blockchain system

was Bitcoin’s Genesis Block. It is the most appropriate for the cybersecurity

ecosystem [14] due to its advantageous features like its decentralized, immutable

nature suitable for peer-to-peer networks. It is the task of every node participating in

the network to verify and validate every new transaction, thus eliminating security

risks and the need for a central authority. Some special nodes present in the network

are miners. They process and confirm transactions using specially designed compu-

tationally powerful computers. The miners [15] perform a very critical mathematical

problem to solve the nonce and generate the proof-of-work, in return the miners

are rewarded. This process adds the transaction records to the public ledger of past

transactions. This way every data and transaction is cryptographically encoded and

secured.

With the advancements in technology, the implementation of IoT is expanding in

different industrial sectors like production, manufacturing and fabrication industries.

This digital transformation of industry led to the fourth industrial revolution, i.e.,

Industry 4.0. It is introducing automation along with new ways of production with

real-time optimization and remote monitoring. As these devices perform such crucial

tasks, it is necessary to secure the critical data handled in the process. So, a new

paradigm for secure data preservation has evolved; it is called blockchain. Blockchain

technology, due to its secure nature, is the most suitable solution to safeguard the

system from various kinds of attacks ranging from common denial-of-service-based

attacks to elaborate cryptanalytic attacks. It has gained a lot of focus in the industry

due to its inherent security qualities, like the application of principles of cryptography

to ensure data immutability and security. Although there are many positive aspects of

blockchain-enabled IIoT, there are some limitations that still persist. The opportunity

cost of integrating blockchain with IoT in specific conditions can be very high due

to certain limitations [16]. Much research work from multiple approaches is being

conducted for ensuring a stable, secure blockchain-IIoT integration. It is an urgent

need of the hour to solve the issues for an efficient inclusion of blockchain in IIoT.

Although there have been several works aiming to overcome the limitations of

blockchain-enabled IIoT, an efficient blockchain solution for IIoT is still limited. To