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What is proof of work?

A consensus mechanism where computers compete to solve a hard arithmetic puzzle, and the winner gets to add the next block.

Miners repeatedly hash candidate blocks until one produces a result below a target. The work is deliberately wasteful: it has no value except that it is provably expensive, which is what makes rewriting history costly. Difficulty adjusts automatically so blocks keep arriving at a target interval however much hardware joins.

Why it matters: it is the mechanism securing Bitcoin, and its energy consumption is the most common criticism of crypto generally. The counter-argument is that the energy cost is the security. Both points are real; which weighs more is a judgement, not a fact.

Related terms

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  • Seed phraseA list of ordinary words, usually twelve or twenty-four, that encodes every private key…
  • ConsensusThe process by which a decentralised network agrees on which transactions happened and in…
  • DeFiDecentralised finance: lending, trading and other financial services provided by smart contracts rather than…
  • Self-custodyHolding your own crypto directly, controlling the private keys yourself, rather than leaving it…

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