miner

Miners are the network participants responsible for adding new blocks to the Bitcoin blockchain. Mining is the process through which transactions are confirmed and the security of the entire network is maintained. To add a block, a miner must solve a computationally difficult puzzle: repeatedly hashing a block header until the resulting hash meets a specific numerical target set by the network. This is called proof of work. The process requires enormous energy expenditure, which is precisely what makes it difficult to cheat. To rewrite history, an attacker would need to redo all that work, which becomes prohibitively expensive as the chain grows.

The hardware used for mining has evolved significantly over Bitcoin's history. In the early years, mining was possible on ordinary computer processors. As more participants joined, the competition increased and miners switched to graphics processing units, which could perform the necessary calculations much faster. Eventually, manufacturers began producing application-specific integrated circuits, known as ASICs, designed exclusively for Bitcoin mining. Modern ASICs are orders of magnitude more efficient than the hardware that came before them. Today, mining at a competitive level requires industrial-scale operations with purpose-built facilities and access to low-cost electricity.

When a miner successfully finds a valid block, they broadcast it to the network and receive two forms of compensation: the block reward, which is a fixed amount of newly created bitcoin, and the sum of all transaction fees included in that block. The block reward halves approximately every four years in an event called the halving. As the block reward decreases over time, transaction fees are expected to play an increasingly important role in funding the security of the network. Miners are therefore not just validators. They are the economic actors whose investment in hardware and energy keeps the Bitcoin network running and trustworthy.