📅 Original date posted:2015-12-25
📝 Original message:On 20.12.2015 18:00, Emin Gün Sirer via bitcoin-dev wrote:
> Instead, we will have the bigger
> pools become more suspicious of signing up new hash power, which is a
> good thing.
Block withholding attacks do not differentiate between small and large
pools. When Eligius and BTCGuild got hit with this, they were far from
the biggest pools at the time.
When my pool, Bitminter, got a new large miner who found 1 block where
average luck would have had them find 3, one of the other miners claimed
they must be withholding blocks. Even if there is no logic or evidence
behind it, after one person cries wolf the others get nervous. This way
even the possibility of block withholding can keep smaller pools from
growing. It takes more hashpower to put a dent in a bigger pool, so you
will see less such panic.
> And we will have small groups of people who have some reason
> for trusting each other (e.g. they know each other from IRC, conferences,
> etc) band together into small pools. These are fantastic outcomes for
> decentralization.
Three guys with 1 TH/s, 2 TH/s and 100 GH/s meet at a conference and
decide to start a private pool? Obviously that doesn't work. Maybe three
people with huge warehouses of miners would work together if they knew
and trusted each other.
Those small miners need to mine with people they don't know to get an
acceptable variance.
If you kill off mining pools then small miners have no way to achieve
acceptable variance and they will disappear. There will only be big
warehouse miners left, the ones who are big enough to solo mine.
That's not helping decentralization.
> Right, it's not clear at all that yelling at people has much effect. As much
> fun as I had going to that meeting with GHash in London to ask them to
> back down off of the 51% boundary, I am pretty sure that yelling at large
> open pools will not scale. We needed better mechanisms for keeping pools
> in check.
I agree. It's very disappointing how most miners and pools handle this
(BTCGuild being the exception). But I do not think block withholding is
a good tool. It can easily destroy small pools, but it won't put a dent
in a pool that goes over 50%.
Block withholding is a tool big pools can use to put smaller competitors
out of business.
And even if it was effective I would not use block withholding to attack
other pools.
> And Miner's Dilemma (MD) attacks are clearly quite effective. This is a
> time when we should count our blessings, not work actively to render
> them inoperable.
Is it? Is there any example of block withholding leading to more
decentralized mining?
If I remember right, GHash being too big ended with BitFury moving some
of their hashpower out of the pool. I don't know where that hashpower
went and whether the problem was solved or merely hidden.
GHash profitability being very low for some time wasn't due to block
withholding, it was a bug that some miners abused to get paid for the
same work multiple times. This made it look like a lot of work was done
while finding few blocks.
> Basically you have the pool pick a secret k for each share, and commit
> to H(k) in the share. Additionally the share commits to a target divider
> D. The PoW validity rule is then changed from H(block header) < T, to be
> H(block header) < T * D && H(H(block header) + k) < max_int / D
>
>
> Thanks, this requires a change to the Bitcoin PoW. Good luck with that!
>
> Once again, this suggestion would make the GHash-at-51% situation
> possible again. Working extra hard to re-enable those painful days
> sounds like a terrible idea.
Block withholding didn't solve the problem back then. And guess what,
those painful days are here right now. China is at 65% and block
withholding isn't solving it.
I was disappointed when GHash got too big and refused to do anything. It
was sad when their miners didn't do anything. Then they used
double-spends to scam a casino. I was shocked that noone cared. Now two
thirds of the bitcoin hashpower is within the control of a single
government. This time I expected noone would care - but I'm still
disappointed. I'm also surprised at the irrational behavior; there are
so many who go out of their way to put their own investments in danger.
For a long time now many miners and pools have been irresponsible with
the hashpower. But block withholding just makes it worse.
Regards,
Geir H. Hansen, Bitminter mining pool
Geir Harald Hansen [ARCHIVE] /
npub1kp…7e3fd
2023-06-07 17:47:06
in reply to nevent1q…nfv2
Author Public Key
npub1kpxa282a99fc93xx30ru3sfmqnyqk3r8aurz3znzxyslhd7felfsg7e3fdPublished at
2023-06-07 17:47:06Event JSON
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"content": "📅 Original date posted:2015-12-25\n📝 Original message:On 20.12.2015 18:00, Emin Gün Sirer via bitcoin-dev wrote:\n\u003e Instead, we will have the bigger\n\u003e pools become more suspicious of signing up new hash power, which is a\n\u003e good thing.\n\nBlock withholding attacks do not differentiate between small and large\npools. When Eligius and BTCGuild got hit with this, they were far from\nthe biggest pools at the time.\n\nWhen my pool, Bitminter, got a new large miner who found 1 block where\naverage luck would have had them find 3, one of the other miners claimed\nthey must be withholding blocks. Even if there is no logic or evidence\nbehind it, after one person cries wolf the others get nervous. This way\neven the possibility of block withholding can keep smaller pools from\ngrowing. It takes more hashpower to put a dent in a bigger pool, so you\nwill see less such panic.\n\n\u003e And we will have small groups of people who have some reason\n\u003e for trusting each other (e.g. they know each other from IRC, conferences,\n\u003e etc) band together into small pools. These are fantastic outcomes for\n\u003e decentralization.\n\nThree guys with 1 TH/s, 2 TH/s and 100 GH/s meet at a conference and\ndecide to start a private pool? Obviously that doesn't work. Maybe three\npeople with huge warehouses of miners would work together if they knew\nand trusted each other.\n\nThose small miners need to mine with people they don't know to get an\nacceptable variance.\n\nIf you kill off mining pools then small miners have no way to achieve\nacceptable variance and they will disappear. There will only be big\nwarehouse miners left, the ones who are big enough to solo mine.\n\nThat's not helping decentralization.\n\n\u003e Right, it's not clear at all that yelling at people has much effect. As much\n\u003e fun as I had going to that meeting with GHash in London to ask them to\n\u003e back down off of the 51% boundary, I am pretty sure that yelling at large\n\u003e open pools will not scale. We needed better mechanisms for keeping pools\n\u003e in check.\n\nI agree. It's very disappointing how most miners and pools handle this\n(BTCGuild being the exception). But I do not think block withholding is\na good tool. It can easily destroy small pools, but it won't put a dent\nin a pool that goes over 50%.\n\nBlock withholding is a tool big pools can use to put smaller competitors\nout of business.\n\nAnd even if it was effective I would not use block withholding to attack\nother pools.\n\n\u003e And Miner's Dilemma (MD) attacks are clearly quite effective. This is a\n\u003e time when we should count our blessings, not work actively to render\n\u003e them inoperable.\n\nIs it? Is there any example of block withholding leading to more\ndecentralized mining?\n\nIf I remember right, GHash being too big ended with BitFury moving some\nof their hashpower out of the pool. I don't know where that hashpower\nwent and whether the problem was solved or merely hidden.\n\nGHash profitability being very low for some time wasn't due to block\nwithholding, it was a bug that some miners abused to get paid for the\nsame work multiple times. This made it look like a lot of work was done\nwhile finding few blocks.\n\n\u003e Basically you have the pool pick a secret k for each share, and commit\n\u003e to H(k) in the share. Additionally the share commits to a target divider\n\u003e D. The PoW validity rule is then changed from H(block header) \u003c T, to be\n\u003e H(block header) \u003c T * D \u0026\u0026 H(H(block header) + k) \u003c max_int / D\n\u003e \n\u003e \n\u003e Thanks, this requires a change to the Bitcoin PoW. Good luck with that! \n\u003e \n\u003e Once again, this suggestion would make the GHash-at-51% situation \n\u003e possible again. Working extra hard to re-enable those painful days \n\u003e sounds like a terrible idea. \n\nBlock withholding didn't solve the problem back then. And guess what,\nthose painful days are here right now. China is at 65% and block\nwithholding isn't solving it.\n\nI was disappointed when GHash got too big and refused to do anything. It\nwas sad when their miners didn't do anything. Then they used\ndouble-spends to scam a casino. I was shocked that noone cared. Now two\nthirds of the bitcoin hashpower is within the control of a single\ngovernment. This time I expected noone would care - but I'm still\ndisappointed. I'm also surprised at the irrational behavior; there are\nso many who go out of their way to put their own investments in danger.\n\nFor a long time now many miners and pools have been irresponsible with\nthe hashpower. But block withholding just makes it worse.\n\nRegards,\nGeir H. Hansen, Bitminter mining pool",
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