One of the first and traditional algorithms devised is the Proof-of-Work. Bitcoin-based blockchain network and Ethereum use this algorithm. Unlike PBFT, PoW does not need consensus based on majority. It is an algorithm that takes enormous computing effort. Only nodes with greater computing power can take up the PoW. The first node that completes the task with the desired output gets a chance to create the block and is compensated for its efforts. PoW typically involves some kind of cryptographic hashing to achieve the desired target or outcome. We will talk of PoW in detail during course of this article