What Is Proof of Work?
Proof of work is Bitcoin's security model: the right to add the next block is earned by burning real-world energy on trillions of guesses, and the chain with the most accumulated work is the truth. It converts electricity into history that is brutally expensive to rewrite.
How It Actually Works
- Miners race to find a number that makes their candidate block's hash meet a difficulty target. Finding it proves effort; anyone can verify the answer instantly.
- The winner broadcasts the block, collects new coins plus fees, and the race restarts. Difficulty auto-adjusts to keep blocks arriving on schedule regardless of how much hardware joins.
- Rewriting an old block means redoing its work and every block after it, faster than the honest network extends the chain. Against Bitcoin's global hashpower, that is economically absurd, which is the security.
Tradeoffs, Stated Plainly
- Energy is the feature and the bill. The cost is what makes attack irrational; the same cost draws environmental criticism and pushes mining toward cheap power.
- Industrial concentration. Competitive mining professionalized into large operations and pools, a centralization pressure worth watching honestly.
- Structural selling. Miners pay power bills in dollars, so mined coins flow to market continuously, the background pressure examined on my learn page.
When It Matters
Understanding why Bitcoin's settled history is trusted, why mining exists, what the halving cuts, and how the model differs from proof of stake, where capital rather than energy is the bond.
Related Terms
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