Are mining pools bad for Bitcoin?

[sktrdie]

This graph kind of scares me: https://blockchain.info/pools
BTC Guild owns 30% of the mining power of the entire network.

I've just started learning how Bitcoin works, but if BTC Guild ever goes up to 50% or so it means that the person in charge of that site (or the address facing the block-chain) has effectively really good chance of getting 5 or even 6 confirmations in a row.

The BTC Guild owner could make a large payment to someone (say to buy a car). The car seller would wait 3-4 confirmations for assurance that the network has accepted it. But then, since the BTCGuild owner owns 50% or more power of the network, he/she could outpace the network after those 3-4 confirmations and essentially get the money back from his car (by double-spending).

This person would be able to make all sorts of payments and overwrite the blocks where the payments were made to get back their money!

What is the Bitcoin community doing to make sure this won't happen?

Thanks,
Luca

[Seccour]

https://bitcointalk.org/index.php?topic=168108.0

Other question ?

[sktrdie]

Interesting thanks.
But from a technical prospective, if a 50% computing power owner would try building his own branch, how would he/she catch up on the largest branch? Since it takes 10 mins to generate a block, wouldn't the main branch continue growing therefore not allowing him/her to catch-up?

[Swordsoffreedom]

They have had 50% before a long while back but pool offsetting would likely occur as people move to other pools

[evansearle42]

If the pool do bad stuff with the hashing power, they will soon lose all their customers...

[mitty]

If the pool do bad stuff with the hashing power, they will soon lose all their customers...

Basically this.

And also right now pools are a necessity for the vast majority of miners.  The variance of solo mining anything less than a few TH/s right now is crazy considering the huge network hashrate/difficulty spikes recently.

[TooDumbForBitcoin]

What is the Bitcoin community doing to make sure this won't happen?

We're putting a very powerful bomb in the car, linked by satellite to the seller's wallet.dat.  If the payment doesn't show up in the seller's wallet within two hours of the purchase, the bomb will go off next time someone turns on the car's ignition. 

[tripppn]

Most of the bigger miners out there are aware of the potential of one pool getting over 50% and would move pools I would think.  I know BTCguild themselves have increases fees in the past to discourage people from using them because they were afraid they might hit that 51% mark.  And for 1 entity to buy enough hardware to get 51% would cost so much money at this point it wouldn't be worth it.  That's one thing about the network getting bigger that is good.

[eleuthria]

The BTC Guild owner could make a large payment to someone (say to buy a car). The car seller would wait 3-4 confirmations for assurance that the network has accepted it. But then, since the BTCGuild owner owns 50% or more power of the network, he/she could outpace the network after those 3-4 confirmations and essentially get the money back from his car (by double-spending).

Pools are only able to remain large as long as people trust them.  We are at the mercy of our members in order to maintain our hash rates.  A double-spend can be detected if anybody is looking at the work the pool serves (it wouldn't be working on the main blockchain, prevblockhash would be different).  It can be *proven* quite shortly after (blockchain.info orphaned blocks page would show the pool doing this), at which point that pool is going to be dead shortly.

As a result, here's a little more to consider:  There is nothing available for easy purchase with Bitcoin that is valuable enough to even remotely tempt a pool operator to do this.  Anything that valuable would be a private deal, and you can be damn sure the person doing that deal wouldn't complete the sale til FAR more than 6 confirmations.  The only method to generate the value that this could be worth it is via an exchange.  Exchanges do not execute withdrawals in the $100k+ range automatically, so by the time this massive withdrawal is even considered, news would be out of the double spend and they'd manually block it from actually going through.


So for a pool to do a double spend...it's virtually impossible to do in a way where the payoff is worth killing off a viable business.  The same is somewhat true of private mining companies:  The attack would be publicly known and odds are would be blocked by the person they're trying to trade with in some way.  The only difference there is the private mining company wouldn't also instantly lose their share of the network since they don't rely on the public to keep their hash rate strong.

[Meni Rosenfeld]

It's not healthy for the ecosystem to have a few huge pools. However, a system such as Multi-PPS may make huge pools unneeded.

[Trongersoll]

It's not healthy for the ecosystem to have a few huge pools. However, a system such as Multi-PPS may make huge pools unneeded.

Due to increasing difficulty, it is possible for a fixed hashrate miner to never ever find a block.

[c1010010]

It's not healthy for the ecosystem to have a few huge pools. However, a system such as Multi-PPS may make huge pools unneeded.

Due to increasing difficulty, it is possible for a fixed hashrate miner to never ever find a block.

I'm not sure I agree with you on this one... anybody can find a block.

[Meni Rosenfeld]

It's not healthy for the ecosystem to have a few huge pools. However, a system such as Multi-PPS may make huge pools unneeded.

Due to increasing difficulty, it is possible for a fixed hashrate miner to never ever find a block.

This is correct. I said that huge pools will be unneeded, not that pools will be unneeded.

[Trongersoll]

It's not healthy for the ecosystem to have a few huge pools. However, a system such as Multi-PPS may make huge pools unneeded.

Due to increasing difficulty, it is possible for a fixed hashrate miner to never ever find a block.

I'm not sure I agree with you on this one... anybody can find a block.

Actually, i forgot to specify "if mining solo".

Yes, anyone "can" find a block. But with constantly rising difficulty, the odds against finding one keep increasing as well.

[luv2drnkbr]

Yes, and it fucking boggles my mind that things like p2pool have as little volume as they have.  Fractional pay-per-share (or at least close, currently share is like 150K or something) and still decentralized... best of both worlds.  Why the hell doesn't everybody use it!?

[DeathAndTaxes]

Yes, and it fucking boggles my mind that things like p2pool have as little volume as they have.  Fractional pay-per-share (or at least close, currently share is like 150K or something) and still decentralized... best of both worlds.  Why the hell doesn't everybody use it!?

Many ASICs don't play nice with p2pool. As an example KNC refresh work function is borked.  When new work comes in it is very slow to react and continues to hash on producing useless hashes.  Now on "normal" bitcoin when there is a work change every 600 seconds it results in a good 1% to 2% lost work.  p2pool essentially is causing a work change every 20 seconds so you are looking at 30% to 60% lost work.   Another way to look at it is for a KNC miner p2pool has a 30%+ fee.  Would you mine on a pool with a 30% fee?

It doesn't HAVE to be that way but until ASIC designers put some thought into latency p2pool is going to be a non-starter.  Beyond the ASIC incompatibility issue, even under GPU era p2pool "struggled" simply because it requires a little more thought, effort, and education.  Many miners are simply lazy.  They want a 1 button "free moniez" machine.  Hell some kept using the broken GUI Miners because learning cgminer was "too hard".  Learning to use p2pool?  Might as well ask them to learn Latin.

[Meni Rosenfeld]

Yes, and it fucking boggles my mind that things like p2pool have as little volume as they have.  Fractional pay-per-share (or at least close, currently share is like 150K or something) and still decentralized... best of both worlds.  Why the hell doesn't everybody use it!?

P2pool uses PPLNS, not PPS.

Some reasons are listed at http://bitcoin.stackexchange.com/questions/2752/what-are-some-reasons-that-a-rational-miner-wont-switch-to-p2pool/2755#2755.

[Hippie Tech]

It's not healthy for the ecosystem to have a few huge pools. However, a system such as Multi-PPS may make huge pools unneeded.

Due to increasing difficulty, it is possible for a fixed hashrate miner to never ever find a block.

This is correct. I said that huge pools will be unneeded, not that pools will be unneeded.

Could the risks involved with pooled mining be minimized/ eliminated if the blockchain/coin itself was the pool and if each share was paid proportionally during the coin's entire lifespan ?

[Shallow]

Since the pool is just a group of people then the miners can simply move.

[Meni Rosenfeld]

It's not healthy for the ecosystem to have a few huge pools. However, a system such as Multi-PPS may make huge pools unneeded.

Due to increasing difficulty, it is possible for a fixed hashrate miner to never ever find a block.

This is correct. I said that huge pools will be unneeded, not that pools will be unneeded.

Could the risks involved with pooled mining be minimized/ eliminated if the blockchain/coin itself was the pool and if each share was paid proportionally during the coin's entire lifespan ?

It seems to me that if the blockchain itself needs to recognize shares it will be very bloated.