What does that mean for you?
A miner gathers payments and competes to propose a block. This process is called proof-of-work. It helps participants agree on a payment history without a central payment operator.
The work does not give a miner permission to spend your bitcoin. A payment still needs the proper approval, and a block still has to satisfy the rules checked by other computers.
Can you picture an example?
Imagine a miner includes a payment without the required signature. Even if the miner has done the computing work, checking computers reject the invalid block. Work and permission to spend are different things.
What should you remember?
Mining can let an accepted block claim new bitcoin allowed by the rules and transaction fees. It does not mean every computer running Bitcoin is a miner. A computer can check the history without competing to add blocks.
Sources
- Bitcoin questions and answers
- How Bitcoin works
- The original Bitcoin paper
- Bitcoin Ecosystem project: source of the chain descriptions in the family note.