Proof of Work

Proof of Work is a system that secures cryptocurrency networks by requiring computers to solve difficult math puzzles before adding new transactions to the ledger. Think of it as a bouncer checking ID—except the "ID" is solving a puzzle that proves you did the computational work. You'll hear this term mainly with Bitcoin, the original cryptocurrency that uses Proof of Work. It matters because it prevents fraud: attacking the network would require solving more puzzles faster than honest computers combined, which is prohibitively expensive. For example, if Sarah wanted to fake a Bitcoin transaction, she'd need to outcompute thousands of miners simultaneously—practically impossible. The tradeoff is that Proof of Work consumes significant electricity.