Basic noob question about hashrate % among top pools

[Savik]

So it seems like the top 5 pools control over 50% of the hashrate:

https://blockchain.info/pools

What's to stop these 5 from getting together and messing with the block chain ledger for their benefit? I understand the miners in these pools are not necessarily controlled, but what if the Top 5 pools changed fees instead of -1% to +1% just for mining with them on a corrupted blockchain? Basically bribing everyone to accept their way?

[Last of the V8s]

So it seems like the top 5 pools control over 50% of the hashrate:

https://blockchain.info/pools

What's to stop these 5 from getting together and messing with the block chain ledger for their benefit? I understand the miners in these pools are not necessarily controlled, but what if the Top 5 pools changed fees instead of -1% to +1% just for mining with them on a corrupted blockchain? Basically bribing everyone to accept their way?

nothing to stop them. they could. but it wouldn't make them much money. they'd soon be found out and ostracised.

there is such a pool - and it's happened before - it just doesn't work for long, as they run out of money or confidence.

note that of these top 5, 3 are owned by the same firm, and most of the top ten are mining on that firm's chips.

they could probably attack now, but meh

[franky1]

.........
if their changes do not meet the rules that nodes/merchants also have then those blocks would get rejected in seconds..
its not about hashrate.. its about rules and whats acceptable to the symbiotic relationship of the network

a block of data is not accepted simply because more hash power was used.

what would actually happen is if the rules were too controversial.. the pool with more hash power could produce more blocks but find the majority of the symbiotic network just rejects more blocks more often.. its that simple.

the end result would be if the nodes that were part of the collaboration would end up in an orphan fight with its peers objecting... which normally ends up with nodes banning communication with each other to avoid the drama.

..

but the end result is .. if a block is not accepted with a merchant, which the pool wants to use to cash out its reward. the pool will realise it has wasted its time and then give in and follow what its favourite merchant prefers. otherwise its just making foreign blocks that the merchant cant accept/understand. and thus the pool cant spend its winnings

its not a simple hash power wins.. there is a symbiotic relationship... best known as CONSENSUS

many people lack understanding of consensus and lack understanding of what makes bitcoin so special.
its multilayered with multiple possible results depending on scenario

[Xavofat]

So it seems like the top 5 pools control over 50% of the hashrate:

https://blockchain.info/pools

What's to stop these 5 from getting together and messing with the block chain ledger for their benefit? I understand the miners in these pools are not necessarily controlled, but what if the Top 5 pools changed fees instead of -1% to +1% just for mining with them on a corrupted blockchain? Basically bribing everyone to accept their way?

there is such a pool - and it's happened before - it just doesn't work for long, as they run out of money or confidence.

GHash.io?  They never actually performed a 51% attack, they just reached a dangerously high amount of the hashrate.  There has never been a 51% attack on the Bitcoin network.

if their changes do not meet the rules that nodes/merchants also have then those blocks would get rejected in seconds..
its not about hashrate.. its about rules and whats acceptable to the symbiotic relationship of the network

a block of data is not accepted simply because more hash power was used.

Mining pools only control the hashrate for now anyway.  It's not like in the inception of Bitcoin, satoshi said "hey Antpool, so you're going to get 16.8% of the hashrate, and BTC.TOP you're going to get 13.3%"...

If they attempted a 51% attack, miners would just move to the numerous other pools available which were not participating in the attack.

[unamis76]

Miners also have an economic incentive to play fair. If they don't do it, they're not contributing to Bitcoins success, thus not contributing to anyone, neither to users, other miners, themselves or their pockets. "Bribing" wouldn't get them far.

[Savik]

Thanks for the replies all. My learning curve is pretty shallow 

[Last of the V8s]

there is such a pool - and it's happened before - it just doesn't work for long, as they run out of money or confidence.

GHash.io?  They never actually performed a 51% attack, they just reached a dangerously high amount of the hashrate.  There has never been a 51% attack on the Bitcoin network.

quite right. ghash and indeed btcguild and an older one all approached/exceeded 51% in their time and did not attack

however i was referring to op's q about pools bribing miners to mine - pool.btc.com does this for now