[[Proof of Work]] (commonly abbreviated as PoW) is a type of consensus mechanism used by some [[blockchain]]-based cryptocurrencies. In a PoW system, the creator of the next block on the blockchain is chosen based on their ability to solve a difficult computational problem.
The computational problem in a proof of work system is designed to be difficult to solve, but easy to verify once a solution is found. This is accomplished using a cryptographic hash function, which takes an input and produces a fixed-size output. The computational problem in a PoW system is to find an input that produces a specific output (or a specific pattern in the output) when hashed.
Solving the computational problem in a PoW system requires a significant amount of computational power, which is why the process is called "mining." Miners compete to find solutions to the computational problem, and the first miner to find a solution is rewarded with a certain number of units of the cryptocurrency.
Bitcoin, the first and most well-known cryptocurrency, uses a proof-of-work consensus mechanism.