<p>P2Pool allows individual miners to band together and find blocks with the reward being shared directly with the miners who participated in finding the block.  If you didn't contribute a pool share during a round, you wouldn't receive a payment for a block found by the round.  The pool has a lower difficulty than the network but greater than an individual miner.  That is, your miner can be submitting shares to the pool but you won't get a pool share unless one of your shares has a difficulty greater than the pool difficulty.  When somebody submits a share with a difficulty greater than the network difficulty, a block is found and everybody who contributed at least one pool share gets part of the reward.</p>

<p>So the trade-off is a high variance since you only get paid if you were participating at the time a block is found and you contributed a pool share.  And finding a block itself is highly variable since it depends on the total hash power of the pool (luck also plays a large role).</p>

<p>Depending on your hash power, you could run your own p2pool or join a p2pool set up by somebody else.  The advantage of joining a common p2pool is it increases your chance to contribute a pool share and thus share in the block reward.</p>

CC BY-SA 3.0
2014-01-10T15:55:07.197Z
2014-01-10T15:55:07.197Z
ScripterRon
<p>The only advantage to shifting miners from using a centralized pool to P2P pools is that it may spread out the hashing power across multiple independent groups - balkanization of the hash compute power. This doesn't solve the problem, it just disrupts it slightly.</p>

<p>A P2P pool is still a collective effort working together as a single block mining entity.  There may not be a central server involved in a P2P pool, but the pool is still collecting transactions and creating a block to add to the blockchain. </p>

<p>If a P2P pool is large enough to produce 51% of the global network hash output, the pool would have the same potential to disrupt blockchain transactions as any other pool - if someone with malicious intent were able to gain control of the block creation process. </p>

<p>So, while a P2P pool might change where the block is created (central vs super node vs any node) and therefore the point of attack, shifting everyone from GHash to <em>one</em> P2P pool won't change the 51% threat.</p>

CC BY-SA 3.0
2014-06-17T21:26:59.660Z
2014-06-17T21:26:59.660Z
dthorpe
<p>I've heard P2P mining pools are the answer to the current threat of mining pools controlling 51% of Bitcoin's hashing power.  Is this true or not true?  Does anyone have a supporting or critical assessment of P2P mining pools? What are the trade offs? Thanks in advance.</p>

<mining-pools><p2pool><majority-attack>
What are the pros and cons of P2P mining pools?
Capitalism Prevails
# What are the pros and cons of P2P mining pools?

(Asked by: username_0 on 2014-01-10)

I've heard P2P mining pools are the answer to the current threat of mining pools controlling 51% of Bitcoin's hashing power. Is this true or not true? Does anyone have a supporting or critical assessment of P2P mining pools? What are the trade offs? Thanks in advance.

**Tags:** mining-pools, p2pool, majority-attack


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## 2 answers

### Answer by username_1 on 2014-01-10. Score: 3

P2Pool allows individual miners to band together and find blocks with the reward being shared directly with the miners who participated in finding the block. If you didn't contribute a pool share during a round, you wouldn't receive a payment for a block found by the round. The pool has a lower difficulty than the network but greater than an individual miner. That is, your miner can be submitting shares to the pool but you won't get a pool share unless one of your shares has a difficulty greater than the pool difficulty. When somebody submits a share with a difficulty greater than the network difficulty, a block is found and everybody who contributed at least one pool share gets part of the reward.

So the trade-off is a high variance since you only get paid if you were participating at the time a block is found and you contributed a pool share. And finding a block itself is highly variable since it depends on the total hash power of the pool (luck also plays a large role).

Depending on your hash power, you could run your own p2pool or join a p2pool set up by somebody else. The advantage of joining a common p2pool is it increases your chance to contribute a pool share and thus share in the block reward.


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### Answer by username_2 on 2014-06-17. Score: 0

The only advantage to shifting miners from using a centralized pool to P2P pools is that it may spread out the hashing power across multiple independent groups - balkanization of the hash compute power. This doesn't solve the problem, it just disrupts it slightly.

A P2P pool is still a collective effort working together as a single block mining entity. There may not be a central server involved in a P2P pool, but the pool is still collecting transactions and creating a block to add to the blockchain.

If a P2P pool is large enough to produce 51% of the global network hash output, the pool would have the same potential to disrupt blockchain transactions as any other pool - if someone with malicious intent were able to gain control of the block creation process.

So, while a P2P pool might change where the block is created (central vs super node vs any node) and therefore the point of attack, shifting everyone from GHash to *one* P2P pool won't change the 51% threat.


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