Glossary
Proof of Work
Proof of Work is a method for securing a blockchain in which participants called miners compete to solve a hard computational puzzle, and the winner earns the right to add the next block of transactions. The work is costly to perform but easy for everyone else to verify.
The close-up. In a Proof of Work system, adding a block requires finding a number that, when combined with the block's data and passed through a hash function, produces an output meeting a difficulty target. There is no shortcut: miners must try enormous numbers of guesses, which consumes real electricity and hardware. When one miner finds a valid answer, it broadcasts the block, and every other participant can confirm it instantly with a single hash. This asymmetry — hard to produce, trivial to check — is what makes the mechanism work. The network adjusts the difficulty so blocks arrive at a roughly steady pace as more or less computing power joins.
The wide shot. Proof of Work answers a foundational question: how can strangers who do not trust each other agree on a shared ledger without a central authority? By tying the right to write history to expended energy, it makes rewriting past blocks expensive, since an attacker would have to redo the accumulated work. It is the original consensus mechanism and the one that secured the first widely used cryptocurrency. Its main trade-offs are energy use and specialized hardware, which motivated alternatives such as Proof of Stake. To see where different networks stand, explore the coins directory. This is informational only — do your own research.