Proof of Work (PoW) is a consensus mechanism used by many blockchain networks, including Bitcoin. In the whitepaper for Bitcoin, Proof of Work was introduced by Satoshi Nakamoto as a method to validate transactions and prevent double-spending in a decentralized system.

Bitcoin was the first PoW blockchain, but the concept of PoW predated Bitcoin, with However, its application in blockchain technology has made it a critical component in maintaining the security and integrity of decentralized networks.