Proof of work (PoW)

In proof of work, miners repeatedly hash candidate blocks until one produces a value below a target set by the network’s difficulty. Finding a valid hash requires vast numbers of attempts, but verifying it is trivial. The winning miner receives the block subsidy and transaction fees. Bitcoin adjusts difficulty every 2,016 blocks, roughly two weeks, to keep block times near ten minutes.

Security comes from the cost of computing power and electricity: rewriting history would require controlling a majority of the network’s hashrate. This links the network to physical infrastructure, specialized chips and energy markets, and makes mining an industrial business sensitive to power prices and hardware efficiency. Critics focus on energy use, while supporters point to its simplicity and resistance to capture.

For allocators, proof of work explains bitcoin’s security model and the economics of listed miners. Example: a miner operating specialized ASIC machines in a low-cost power region competes for bitcoin block rewards, with profitability tied to bitcoin’s price, network difficulty and electricity costs.