Proof of Work (PoW)
mining · blockchain · consensus
A consensus mechanism that makes block production require verifiable computational work.
Proof of Work (PoW) requires block producers to find a block hash below a difficulty target. The search is costly and probabilistic, while verifying the resulting hash is inexpensive.
In Nakamoto-style consensus, nodes select the valid chain with the most accumulated proof of work. Confirmations provide probabilistic finality because replacing deeper history requires producing a competing chain with enough work.
Security depends on the cost, availability, and distribution of compatible hash power together with node validation and economic incentives. A large attacker can reorganize recent blocks, censor transactions, or double-spend its own payments; proof of work does not authorize arbitrary theft or invalid rule changes.
PoW consumes energy and often favors specialized hardware, cheap power, efficient operations, and well-connected pools. Its objective work history is useful for new-node synchronization, while energy use, hardware concentration, and external environmental costs remain material tradeoffs.
Related terms
Proof of Stake (PoS)
→A family of consensus mechanisms in which validators commit stake to propose, attest to, and finalize blocks.
consensus · blockchain
Miner
→A proof-of-work participant that builds or searches candidate blocks and earns revenue when an accepted block is found.
role · mining
Hash rate
→The number of proof-of-work hash attempts performed per second by mining hardware or an entire network.
mining · security
Mining Difficulty
→Mining difficulty measures how hard it is to find a valid proof-of-work block and adjusts to keep average block times near target.
mining · security · blockchain
Nakamoto Consensus
→Probabilistic consensus in which nodes validate rules and prefer the valid chain with the most accumulated proof of work.
consensus · proof-of-work