Proof of work is the original crypto consensus mechanism, first used by Bitcoin. Proof of work and mining are closely related ideas. The reason it’s called “proof of work” is because the network requires a huge amount of processing power. Proof-of-work blockchains are secured and verified by virtual miners around the world racing to be the first to solve a math puzzle. The winner gets to update the blockchain with the latest verified transactions and is rewarded  by the network with a predetermined amount of crypto.