GlossaryIntermediate
Proof of Work
A consensus method that uses computational work to help choose and secure new blockchain blocks.
Proof of work is a consensus mechanism in which miners compete to solve a computational puzzle. A valid result lets a miner propose a block, while other network participants verify the work and the block's transactions.
The required computation makes rewriting recent history costly, but it also uses energy and can concentrate activity among participants with efficient hardware. See Kaavon's "51% Attack" glossary definition for what happens if a single party ever controls enough of that computing power.
Examples
- Bitcoin uses proof of work to coordinate block production.
- A miner's computing effort does not allow it to spend coins without a valid private-key signature.