<p>Miners regularly send "shares" to the pool server. The shares are solution to a low-difficulty bitcoin puzzle. Each share stands some chance of being a solution to the current bitcoin puzzle, of much higher difficulty.</p>

<p>By sending shares, miners show that they are working on the problem, and may potentially reveal its solution to the pool server. They are often remunerated based on the number of shares they find, and of their difficulty.</p>

CC BY-SA 3.0
2017-11-06T22:41:31.170Z
Can you elaborate more on the answer. Solo miner calculates SHA-256 of block header, this is the 'normal puzzle'.  What is the low-difficulty puzzle?
croraf
CC BY-SA 3.0
2017-11-07T05:21:24.573Z
The low difficulty "puzzle" is just like the normal "puzzle" except the target is much higher so the difficulty is lower (it's an inverse relationship). This means that a miner is more likely to find a share and the pool can track that the miner is actually doing work. By the randomness property of hashes, a miner will eventually find a hash that is also less than the actual network target (and thus be less than the pool target) and that block is what the pool submits to the network.
Ava Chow
CC BY-SA 3.0
2017-11-07T08:48:53.540Z
You should perhaps post this as an answer.
croraf
CC BY-SA 4.0
2019-09-14T16:26:52.600Z
rephrasing, let say that the current difficulty is to find a hash of `transaction` starting with 17 zeros, if a miner finds a hash starting with 8 zeros then it is a share proving that the miner did some work. If this is the case, the miner could also do the minimum amount of work to solve these kind of puzzles. But perhaps you are rewarded based on the difficulty of your shares (if you find hash starting with 10 zeros, you might get a bigger part of the reward because it proves that you worked more). No idea if this is what is implemented though.
David 天宇 Wong
CC BY-SA 4.0
2019-09-14T16:27:57.450Z
these explanations also do not say how the pool prevents a miner who finds a solution from not sharing it. **EDIT**: of course, the `transaction` that everyone is trying to mine uses the pool's address as recipient of the coinbase
David 天宇 Wong
CC BY-SA 4.0
2020-04-24T11:54:32.823Z
The pool probably only sends the header to the miner. That way, even if the miner finds the solution, it only has the header and has no clue about the block contents required for publishing it.
raugfer
CC BY-SA 3.0
2017-11-06T20:09:53.127Z
2017-11-06T20:09:53.127Z
Charles Bouillaguet
<p>I understand that the header given to some miner contains hash of Coinbase that goes to servers address. Thus the miner cannot take the reward.</p>

<p>Also in the simplest setup the server gives miner a range of nonces to check and the range that miner checks is proportional to his hashing power and proportional to the reward.</p>

<p>How does server ensure miner checked that range?</p>

CC BY-SA 3.0
2017-11-06T08:37:53.483Z
Possible duplicate of [How do mining pools work?](https://bitcoin.stackexchange.com/questions/21769/how-do-mining-pools-work)
rny
CC BY-SA 3.0
2017-11-06T16:30:10.133Z
That question is an overview of mining pools. My question is specific, not answered within the scope of that question. The only thing I found there is "To do this there's specific software installed on the admin's server that takes care of making sure each miner is doing the work requested." I'm interested in how that "software" works.
croraf
<mining-pools><mining-theory>
How does mining pool ensure the miner works on the problem?
croraf
# How does mining pool ensure the miner works on the problem?

(Asked by: username_0 on 2017-11-05)

I understand that the header given to some miner contains hash of Coinbase that goes to servers address. Thus the miner cannot take the reward.

Also in the simplest setup the server gives miner a range of nonces to check and the range that miner checks is proportional to his hashing power and proportional to the reward.

How does server ensure miner checked that range?

**Tags:** mining-pools, mining-theory

> **Comments:**
> **username_1**: Possible duplicate of [How do mining pools work?](https://bitcoin.stackexchange.com/questions/21769/how-do-mining-pools-work)  
> **username_0**: That question is an overview of mining pools. My question is specific, not answered within the scope of that question. The only thing I found there is "To do this there's specific software installed on the admin's server that takes care of making sure each miner is doing the work requested." I'm interested in how that "software" works.  

---

## 1 answers

### Answer by username_2 on 2017-11-06. Score: 6

Miners regularly send "shares" to the pool server. The shares are solution to a low-difficulty bitcoin puzzle. Each share stands some chance of being a solution to the current bitcoin puzzle, of much higher difficulty.

By sending shares, miners show that they are working on the problem, and may potentially reveal its solution to the pool server. They are often remunerated based on the number of shares they find, and of their difficulty.

> **Comments:**
> **username_0**: Can you elaborate more on the answer. Solo miner calculates SHA-256 of block header, this is the 'normal puzzle'.  What is the low-difficulty puzzle?  
> **username_3**: The low difficulty "puzzle" is just like the normal "puzzle" except the target is much higher so the difficulty is lower (it's an inverse relationship). This means that a miner is more likely to find a share and the pool can track that the miner is actually doing work. By the randomness property of hashes, a miner will eventually find a hash that is also less than the actual network target (and thus be less than the pool target) and that block is what the pool submits to the network.  
> **username_0**: You should perhaps post this as an answer.  
> **username_4**: rephrasing, let say that the current difficulty is to find a hash of `transaction` starting with 17 zeros, if a miner finds a hash starting with 8 zeros then it is a share proving that the miner did some work. If this is the case, the miner could also do the minimum amount of work to solve these kind of puzzles. But perhaps you are rewarded based on the difficulty of your shares (if you find hash starting with 10 zeros, you might get a bigger part of the reward because it proves that you worked more). No idea if this is what is implemented though.  
> **username_4**: these explanations also do not say how the pool prevents a miner who finds a solution from not sharing it. **EDIT**: of course, the `transaction` that everyone is trying to mine uses the pool's address as recipient of the coinbase  
> **username_5**: The pool probably only sends the header to the miner. That way, even if the miner finds the solution, it only has the header and has no clue about the block contents required for publishing it.  

---

