And if half of the miners turn off their hardwares ?

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Quote from: btcusr on October 26, 2013, 04:23:05 AM

This is also a way to inflate bitcoins..

1. Shutdown 50% miners; half of usual blocks found; (25 * 3 * 24 * 14) for two weeks; >> 25200 BTC
2. Difficulty down to half of usual
3. Bring those 50% miners back, (25 * 12 * 24 * 14) for another two weeks; >> 100800 BTC
4. Usual for a month (25 * 6 * 24 * 28); >> 100800; excess, 25200 BTC

May be someone is already doing this. Right?

Difficulty adjustment is based on block count, not time. With half the miners gone, difficulty will take 4 weeks to adjust. And when they double the hashing power again, it will take 1 week. So essentially, the result will be that it takes 5 weeks to mine the blocks that usually takes 4 weeks.

btcusr

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@_vjy

This is also a way to inflate bitcoins..

1. Shutdown 50% miners; half of usual blocks found; (25 * 3 * 24 * 14) for two weeks; >> 25200 BTC
2. Difficulty down to half of usual
3. Bring those 50% miners back, (25 * 12 * 24 * 14) for another two weeks; >> 100800 BTC
4. Usual for a month (25 * 6 * 24 * 28); >> 100800; excess, 25200 BTC

May be someone is already doing this. Right?

razorfishsl

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A point I made months ago…..

Also consider if two or three pool operators decided to work together……. with a high speed link between the 3….

Think about a very big country where cheap electronics comes from…….

algorista

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Quote from: Meni Rosenfeld on October 25, 2013, 02:44:45 AM

...
As for the original question re a week, that's exp(-7*1440/10) = 1.7 E-438.

Thanks for the additional information.
This is certainly a very interesting subject.

algorista

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Quote from: Morbid on October 25, 2013, 02:17:53 AM

if you leave the biggest pool alive and pull the plug on three smaller pools at the same time then you pretty much gonna have 51% attack...

Exactly, and this is a serious thing to think about.

Anon136

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Quote from: Morbid on October 25, 2013, 02:17:53 AM

if you leave the biggest pool alive and pull the plug on three smaller pools at the same time then you pretty much gonna have 51% attack...

thats true but its important to understand the limitations of a temporary 51% attack. You cant just say "mowa ha ha ha" and write yourself 1 trillion bitcoins. Now a sustained 51% attack could be a more serious problem but there is no reason to expect the above outlined situation to lead to a sustained 51% attack.

petersiddle98

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Quote from: Morbid on October 24, 2013, 12:38:47 PM

im more worried about operation involving governmental agencies around the globe shutting down most major pools at once. we need to be more concerned aboud pool safety imho.

Who cares about pool safety when everyone isn't making money mining it Sad

Meni Rosenfeld

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Quote from: algorista on October 24, 2013, 07:45:15 AM

Quote from: bitcoinator on October 24, 2013, 04:53:25 AM

Mining a block takes 10 minutes in average. But it may take 10 seconds or 10 weeks as well. Did anybody make a calculation, what's the probability that it will take a week to mine a single block under normal conditions (i. e. when difficulty is adequate to the total hashing power)?

I've seen many guesses and opinions about but a real calculation done by someone who understands the subject has not yet been done, or at least published.

It's a trivial calculation, and numbers have been published multiple times.

Quote from: DeathAndTaxes on October 24, 2013, 12:23:34 PM

Quote from: algorista on October 24, 2013, 07:45:15 AM

Quote from: bitcoinator on October 24, 2013, 04:53:25 AM

Mining a block takes 10 minutes in average. But it may take 10 seconds or 10 weeks as well. Did anybody make a calculation, what's the probability that it will take a week to mine a single block under normal conditions (i. e. when difficulty is adequate to the total hashing power)?

I've seen many guesses and opinions about but a real calculation done by someone who understands the subject has not yet been done, or at least published.

Bitcoin mining is a poisson distribution. It is far easier to just use a poisson distribution calculator (online, graphing calculator, mathematica).

In 1 hour the expected # of events (blocks) is 6. The probability that there will be 1 or less is ~1.7%
In 2 hours the expected # of events (blocks) is 12. The probability that there will be 1 or less is ~0.01%

In 24 hours the expected # of events (blocks) is 144. The probability that there will be 1 or less is essentially 0 (4.198 E-61)

Use the right terms, Bitcoin mining is a Poisson process. The number of blocks in a period of time follows the Poisson distribution.

The numbers are good but I think it is more useful to think in terms of the time until the next block, which follows the exponential distribution. If the average is 10 minutes, the chance that the next block will be later than a day (1440 minutes) is exp (-1440/10) = 2.9 E-63.

As for the original question re a week, that's exp(-7*1440/10) = 1.7 E-438.

bitcoinator

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Quote from: DeathAndTaxes on October 24, 2013, 12:23:34 PM

In 24 hours the expected # of events (blocks) is 144. The probability that there will be 1 or less is essentially 0 (4.198 E-61)

Whew. Thank you very much, this answers my question :-)

Morbid

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if you leave the biggest pool alive and pull the plug on three smaller pools at the same time then you pretty much gonna have 51% attack...

algorista

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Quote from: Anon136 on October 25, 2013, 12:30:11 AM

Quote from: algorista on October 24, 2013, 11:09:07 PM

I think the greed is destroying the decentralization of Bitcoin with an excessive concentration in the pools.
But that still does not have have a simple solution.

The moment that centralization became an issue people would switch to less populated pools and the network would become less centralized and the problem would self correct. Thats the beauty of the situation. the equipment that is operating these pools is spread all over the world and can firctionlessly move between pools so the appearance of centralization that we see from that pi chart up there is very misleading.

That is a good point to think about, but often people can not see beyond their options, they just choose whichever is easier and profitable for them.
A larger pool means gains more stable and therefore there is a tendency of centralization over the years.

Anon136

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Quote from: algorista on October 24, 2013, 11:09:07 PM

I think the greed is destroying the decentralization of Bitcoin with an excessive concentration in the pools.
But that still does not have have a simple solution.

The moment that centralization became an issue people would switch to less populated pools and the network would become less centralized and the problem would self correct. Thats the beauty of the situation. the equipment that is operating these pools is spread all over the world and can firctionlessly move between pools so the appearance of centralization that we see from that pi chart up there is very misleading.

algorista

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Quote from: DeathAndTaxes on October 24, 2013, 11:24:31 PM

Quote from: algorista on October 24, 2013, 11:09:07 PM

I think the greed is destroying the decentralization of Bitcoin with an excessive concentration in the pools.
But that still does not have have a simple solution.

Pools are no more concentrated than they were two years ago. If anything they are marginally less concentrated and a significantly higher solo %.

We have a historical record of this information? an chart would be great to understand that.

My reasoning when I made the statement is grounded *also* on the following link.

https://en.bitcoin.it/wiki/P2Pool

Quote from: link

Decentralized payout pooling solves the problem of centralized mining pools degrading the decentralization of Bitcoin and avoids the risk of hard to detect theft by pool operators.

DeathAndTaxes

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Gerald Davis

Quote from: algorista on October 24, 2013, 11:09:07 PM

I think the greed is destroying the decentralization of Bitcoin with an excessive concentration in the pools.
But that still does not have have a simple solution.

Pools are no more concentrated than they were two years ago. If anything they are marginally less concentrated and a significantly higher solo %.

algorista

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It's got electrolytes

I think the greed is destroying the decentralization of Bitcoin with an excessive concentration in the pools.
But that still does not have have a simple solution.

Anon136

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Quote from: Morbid on October 24, 2013, 12:38:47 PM

im more worried about operation involving governmental agencies around the globe shutting down most major pools at once. we need to be more concerned aboud pool safety imho.

it wouldn't be pleasant but it wouldn't be the end of the world ether. most miners would just operate without a pool, even with out expecting to profit monetarily just to spite the ass holes who attacked their pools. i know i surely would and if you took a pole I'm willing to bet it would corroborate my claim.

algorista

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Quote from: Morbid on October 24, 2013, 12:38:47 PM

im more worried about operation involving governmental agencies around the globe shutting down most major pools at once. we need to be more concerned aboud pool safety imho.

+1

Morbid

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im more worried about operation involving governmental agencies around the globe shutting down most major pools at once. we need to be more concerned aboud pool safety imho.

justusranvier

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Quote from: DeathAndTaxes on October 24, 2013, 12:23:34 PM

In 1 hour the expected # of events (blocks) is 6. The probability that there will be 1 or less is ~1.7%
In 2 hours the expected # of events (blocks) is 12. The probability that there will be 1 or less is ~0.01%

In 24 hours the expected # of events (blocks) is 144. The probability that there will be 1 or less is essentially 0 (4.198 E-61)

Using the same numbers you can say:

1 hour block times should happen approximately once every 58 hours.
2 hour block times should happen approximately once every 80 days.
1 day block times should happen approximately once every 8*10⁴⁵ universe lifetimes (34 billion years).

DannyHamilton

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Quote from: DeathAndTaxes on October 24, 2013, 12:23:34 PM

In 24 hours the expected # of events (blocks) is 144. The probability that there will be 1 or less is ~~essentially 0~~ (4.198 E-61)

So you're saying there's still a chance?
Grin

Topic: And if half of the miners turn off their hardwares ? (Read 3009 times)