Bitcoin and chains · 13 / 127 · 2 min
Mining pools
The pool pays you. The chain pays the pool. A pool with enough of the work can matter to the history.
The chain pays the pool. The pool pays you, on its formula.
A worked case
A miner points machines at a pool because the payouts are smoother. The pool grows until it is a large share of the work. The miner's payout is still the pool's promise. The chain never contracted with the miner.
Who is paid
Your machines point at a pool. The pool collects the block reward and pays you by its own formula. The formula is the pool's, and the pool can change it.
A large share
A pool that does most of the work can, in principle, rewrite recent blocks. In 2014 one pool grew large enough that miners left it. The share falling was a choice by the miners, not a rule of the chain.
A pool that grew too large
In 2014 the mining pool GHash.io grew towards half of the bitcoin network's hashrate. A pool with most of the work can rewrite recent history. That is the whole of a majority attack: not a clever trick, a weight of machines. Miners noticed, and many left the pool. The share fell because the miners moved, not because the software forbade a large pool.
The payout you receive is still the pool's formula. The chain paid the block to the pool. If you cannot name the pool, you cannot say who can change your payout.
Read it yourself
These links are the record. They are not a recommendation, and they are not instructions. A news story or a court paper can still be wrong about a detail. The check does not change because a famous name is in the story.
Apply the check
Open a question. The line is about this topic. It is not a verdict that anything is safe.
The pool, which takes a fee and pays the rest on its formula.
The pool operator.
The pool, by changing the payout or withholding it. A large pool, by the weight of its work.
Check yourself
Write it in your own words. The course's answer opens after that. Nothing is sent.
After this you can name the pool, and ask what happens if it grows.