Bitcoin Mining’s Three Body Problem • Hacker News Board

Re: Bitcoin Mining’s Three Body Problem

#111

Post by qes » Wed, Jun 03, 2020, 3:04 PM UTC

jkhdigital wrote: post #28

hn_acc_2 wrote: post #19

Earlier quoted context omitted.

https://www.crypto51.app/coins/BTC.html You could pay $384k to hire miners to 51% attack BTC right now (that is, if NiceHash had the capacity). If you cut the hash rate that much the cost would be only $400 or so. Does it sound like a secure trustless currency if anyone can pay $400 to gain 51% majority? EDIT: 51% attack != rewrite blockchain

Correction: pay $400/hr to gain a temporary majority in the block mining lottery. You can do a variety of things with that majority power, but “rewriting history” is a bit misleading. Yes, you can probably get the network to discard some previously accepted blocks, but this only allows you to invalidate your own transactions plus the transactions that depend on them. Furthermore, any blocks that were mined under high…

Correction (where are you folks learning math? $400/hour, do you even have common sense?):

0.009 BTC/PH/day to buy from NiceHash (https://www.nicehash.com/algorithm/sha256)

100,000 PH/day total hashrate of BTC network (https://www.blockchain.com/charts/hash-rate)

That's 450 BTC/day to buy 50% of the hash rate (as if you even could, that in itself is a ridiculous notion - NiceHash says they have only 300 PH).

Or 18.75 BTC/hour. Or $185,000/hour.

Of course, you're not going to buy 50% of the network's currently running hash power. You'd likely need closer to 100% of the network's current hash power to gain 51%.

Re: Bitcoin Mining’s Three Body Problem

#112

Post by qes » Wed, Jun 03, 2020, 3:11 PM UTC

a1369209993 wrote: post #64

trixie_ wrote: post #26

Earlier quoted context omitted.

There's a big difference between rewriting all history and rewriting a portion of it during an attack which costs 400k per hour. Also people may misinterpret 'rewriting history' as the ability to to change coins sent from A -> B to A -> C. Which it is not. Not saying an attack still isn't bad, but let's be clear what the extent of the damage could and could not be.

1: It's actually, under your proposal, "rewriting a portion of [history] during an attack which costs 400 [ not 400 thousand] [dollars] per hour". 2: If you are A (and regardless of whether you're also C) and you sent money to B during the 400$/hr (less than a high-profile lawyer, and probably faster to boot) attack, then yes, changing coins sent from A -> B to A -> C is exactly what you can do.

> which costs 400 [not 400 thousand] [dollars] per hour

No, it's $400,000 per hour.

0.009 BTC/PH/day to buy from NiceHash (https://www.nicehash.com/algorithm/sha256)

100,000 PH/day total hashrate of BTC network (https://www.blockchain.com/charts/hash-rate)

That's 450 BTC/day to buy 50% of the hash rate (as if you even could, that in itself is a ridiculous notion - NiceHash says they have only 300 PH).

Or 18.75 BTC/hour. Or $185,000/hour.

Of course, you're not going to buy 50% of the network's currently running hash power. You'd likely need closer to 100% of the network's current hash power to gain 51%. So, $400,000/hr.

I mean really, does it pass any sort of common sense test that you could 51% the bitcoin network for $400 per hour?

Re: Bitcoin Mining’s Three Body Problem

#113

Post by a1369209993 » Wed, Jun 03, 2020, 4:29 PM UTC

qes wrote: post #112

a1369209993 wrote: post #64

Earlier quoted context omitted.

1: It's actually, under your proposal, "rewriting a portion of [history] during an attack which costs 400 [ not 400 thousand] [dollars] per hour". 2: If you are A (and regardless of whether you're also C) and you sent money to B during the 400$/hr (less than a high-profile lawyer, and probably faster to boot) attack, then yes, changing coins sent from A -> B to A -> C is exactly what you can do.

> which costs 400 [not 400 thousand] [dollars] per hour No, it's $400,000 per hour. 0.009 BTC/PH/day to buy from NiceHash ( https://www.nicehash.com/algorithm/sha256 ) 100,000 PH/day total hashrate of BTC network ( https://www.blockchain.com/charts/hash-rate ) That's 450 BTC/day to buy 50% of the hash rate (as if you even could, that in itself is a ridiculous notion - NiceHash says they have only 300 PH). Or 18.75 BT…

> The hash rate could be 1/1000 of what it is today

> If you cut the hash rate that much the cost would be only $400 or so.

> during an attack which costs 400k per hour

> under your proposal [of reducing the hash rate by a factor of 1000]

Perhaps I should have been more explicit, but it certainly isn't necessary.

> So, $400,000/hr.

Which, if the hash rate was "1/1000 of what it is today", would be reduced to 400$/hr.

Re: Bitcoin Mining’s Three Body Problem

#114

Post by a1369209993 » Wed, Jun 03, 2020, 4:33 PM UTC

qes wrote: post #110

a1369209993 wrote: post #67

Earlier quoted context omitted.

True, but if such a attack only costs 400$/hr there's going to quite a lot of them to do things about.

It's almost like if it were true that if it only cost $400/hr to 51% attack the BTC chain, we would actually see it happening much more often.

Exactly, that's (very roughly) why it not only is, but must be, that you cannot, in fact, reduce the hash rate significantly without compromising the integrity of the ledger.

Re: Bitcoin Mining’s Three Body Problem

#115

Post by rodonn » Wed, Jun 03, 2020, 4:51 PM UTC

tdhttt wrote: post #37

trixie_ wrote: post #4

'Bitcoin is the product of hashpower. The industry wouldn’t exist without incentivizing miners to continuously invest in hardware and burning electricity to augment Bitcoin network’s settlement assurance' I think this is a common misconception. People don't need to continually invest in mining hardware to keep it going. The entire Bitcoin network could technically be run off a single Rasberry Pi. The network hash rat…

> The network hash rate is only so high because the ROI is there, but without it, people would still be mining. Can you expand on that? What would be the incentive for the miners then? What happens when all blocks are mined?

If ROI goes down, fewer miners will mine. When all blocks are mined, transaction fees will be the main source of incentive to mine.

Re: Bitcoin Mining’s Three Body Problem

#116

Post by noxer » Wed, Jun 03, 2020, 6:20 PM UTC

>"If mining operations migrate to more diverse locations in the future and become less concentrated on a single power source, this cycle will cease to play such a significant role."

Why should that happen? After the initial very diverse mining, it only ever got more concentrated to places with cheap energy. The place my change but there will always be an optimum place.

Re: Bitcoin Mining’s Three Body Problem

#117

Post by Dylan16807 » Wed, Jun 03, 2020, 7:32 PM UTC

a1369209993 wrote: post #114

qes wrote: post #110

Earlier quoted context omitted.

It's almost like if it were true that if it only cost $400/hr to 51% attack the BTC chain, we would actually see it happening much more often.

Exactly, that's (very roughly) why it not only is , but must be , that you cannot, in fact, reduce the hash rate significantly without compromising the integrity of the ledger.

That depends on how you define integrity.

If we cut the hash rate tenfold, which is definitely significant, you'd still need to find someone who has hundreds of thousands of dollars of motivation to perform an attack. Having that motivation is hard when it takes a huge amount of double spending all at once, the attack will damage the integrity of the coin, and clients can be modified to be highly resistant to it.

Re: Bitcoin Mining’s Three Body Problem

#118

Post by perl4ever » Thu, Jun 04, 2020, 1:31 AM UTC

thaumasiotes wrote: post #79

perl4ever wrote: post #72

Earlier quoted context omitted.

To bring $1 worth of US currency into existence, it only costs a fraction of that amount. But to bring $1 worth of bitcoin into existence, it costs $1. So, it seems obvious to me hash based currency is a virus that is many orders of magnitude less efficient, but many people seem impossible to convince of this.

> To bring $1 worth of US currency into existence, it only costs a fraction of that amount. > But to bring $1 worth of bitcoin into existence, it costs $1. But this just says the seigniorage value of creating bitcoins is 0. It doesn't say the total value of creating bitcoins is 0 -- they might continue to produce value after being created! For example, the situation you describe applies in full to actual physical cur…

I wasn't confident enough to declare bitcoin is equivalent to, say, gold. But it sounds like you are, so maybe that is correct - bitcoin is just as bad as gold, or conversely, gold is just as bad as bitcoin. We observe that fiat currency has mostly driven out metal currency, and I'm inclined to think that is because it is more efficient in using resources.

As you say, currency constantly generates value. It is useful. But -100% of the face value is a large burden to start with. How large, relatively speaking? Well, I don't know exactly what to compare it to, but intuitively the value of currency would be related to interest rates, which have been really low for quite a while in the developed world.