Research Article EnergyEfficientMultiprocessingSoloMiningAlgorithmsfor PublicBlockchainSystems ZeeshanRaza , 1 IrfanulHaq , 1 MuhammadMuneeb , 1 andOmairShafiq 2 1 Department of Computer and Information Sciences (DCIS), Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad 45650, Pakistan 2 School of Information Technology, Carleton University, Ottawa, ON, Canada Correspondence should be addressed to Zeeshan Raza; zeeshan.raza@yahoo.com Received 30 March 2021; Revised 29 June 2021; Accepted 30 August 2021; Published 31 October 2021 Academic Editor: Jiwei Huang Copyright © 2021 Zeeshan Raza et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Blockchain as a decentralized distributed ledger is revolutionizing the world with a secure design data storage mechanism. In the case of Bitcoin, mining involves a process of packing transactions in a block by calculating a random number termed as a nonce. e nonce calculation is done by special nodes called miners, and all the miners follow the Proof of Work (PoW) mining mechanism to perform the mining task. e transaction verification time in PoW-based blockchain systems, i.e., Bitcoin, is much slower than other digital transaction systems such as PayPal. It needs to be quicker if a system adapts PoW-based blockchain solutions, where there are thousands of transactions being computed at a time. Besides this, PoW mining also consumes a lot of energy to calculate the nonce of a block. Mining pools resulting into aggregated hashpower have been a popular solution to speed up the PoW mining, but they can be attacked by using different types of attacks. Parallel computing can be used to speed up the solo mining methods by utilizing the multiple processes of the contributing processors. In this research, we analyze various consensus mechanisms and see that the PoW-based blockchain systems have the limitations of low transaction confirmation time and high energy consumption. We also analyze various types of consensus layer attacks and their effects on miners and mining pools. To tackle these issues, we propose parallel PoW nonce calculation methods to accelerate the transaction verification process especially in solo mining. We have tested our techniques on different difficulty levels, and our proposed techniques yield better results than the traditional nonce computation mechanisms. 1.Introduction Blockchain has introduced a new transaction/data storage mechanism that provides better transparency, is more se- cure, enables business between untrusted parties, and helps in reducing fraud [1]. e use of blockchain technology is not limited to the cryptocurrencies now but is also being used in other industries like transportation, automotive industry, supply chain management [2], healthcare [3, 4], and agriculture sector [5, 6]. Blockchain offers advantages like transparency and immutability, but it also has some limitations specially when the PoW is used in solo mining. Proof of Work (PoW) [7, 8] is one of the first blockchain mining algorithms popularized by Bitcoin, and now many blockchain technologies use it for transactions confirmation. e principle behind PoW is to solve a mathematical puzzle, and a reward is given to the miners who solve this complex problem. In PoW mining, miners need to pack transactions in a block and use a brute-force mechanism to find a nonce, which satisfies a given difficulty level. All the miners are given equal opportunity to find the nonce, and in case of success, they are given mining rewards as well as transaction fees. As mentioned in the literature, such as [9], the mining process works approximately as shown in equation (1). Symbol + is used to denote the concatenation of strings. e cryptographic problem of computing a double SHA256 hash has to be solved by a miner denoted by M. s � SHA256 SHA256 n + h + s′ + x (  ( . (1) Hindawi Scientific Programming Volume 2021, Article ID 9996132, 13 pages https://doi.org/10.1155/2021/9996132