The Eyal & Sirer paper is pretty interesting - they basically point out that there is actually some game theory involved in when miners should reveal that they mined a block to compete most effectively with their fellows. If a pool can set up a situation where they mine a block and wait X seconds to reveal it, they can force other miners to waste X seconds of has power and gain an advantage.
It looks like a result with complex implications - eg, maybe making it impossible for new miners to set up unless they have a meaningful advantage in operating costs instead of just parity with the entrenched players. It is hard to tell because market reality is a mess but if there is a meaningful strategic choice to be made beyond simply announcing a block when it is mined then there is a lot of room for weird equilibriums even if the paper's specific analysis turns out to have flaws.
This can have another explanation as well: the moment a block is found, the miner starts building on top of the previous block but hasn't constructed a new full block of transactions yet as that costs a bit of time to calculate and distribute. In this period, a new block could be found.
Blocks are Merkle trees, only the head transaction contains global seed. So, for one to mine block, one needs to walk Merkle tree up from head and then finish work with small amount of data in the block header.
Thus, the time spent mining block is directly dependent on the logarithm of number of transactions in the block.
If one can mine a block with 3000 transactions (11-12 hashes to the header) in 10 minutes, one can mine a block with one transaction (1 hash to header) about ten times as fast.
The construction of the block is negligible if we talk about complete block mining time.
>If one can mine a block with 3000 transactions (11-12 hashes to the header) in 10 minutes, one can mine a block with one transaction (1 hash to header) about ten times as fast.
Huh? Surely the attempts for both take exactly the same amount of time after you've initially constructed the block, you're calculating only a single hash for each attempt.
> If a pool can set up a situation where they mine a block and wait X seconds to reveal it, they can force other miners to waste X seconds of has power and gain an advantage.
How is it wasted if they work on the current chain? If they find a block during those X seconds, they'll propagate it before the waiting pool does. The waiting pool will then just lose the revenue from the block they put on hold. They're the ones wasting mining time when that happens, while the others never do.
If you mine a block without revealing it, not only are you the only one that can mine the next block after that, but everyone is mining on the "wrong head". There's of course the risk that someone finds a different head in the meantime, but otherwise, you waste competitors' resources, while you get an advantage on the next block.
What makes it more likely that your first block ends up the next head and you're not wasting your own time on the second one if someone beats you to the first one while you're holding off?
They are not mining on the wrong head. They are mining on the current head. If they find a block it will be accepted as the new head and the withheld block will be rejected, so it's not wasted mining time at all.
1. They don't have to wait until another miner finds a block, they can just wait "for some time" and then release their block. All that time gives them the edge for the next block.
2. My understanding is that if two different blocks are found concurrently for the same head, then the network waits for the next block to select which "new head" is accepted. I.e. when there are competing chains, the longer chain wins. So I could imagine that a strategy could be to wait until some other miner announces their block and release yours precisely at that time, hence creating two competing chains. But you presumably have an edge because you have already been mining for a while on top of your block.
In a lottery, the more tickets you buy, the higher your chances to have the winning number.
If we played with a roulette and said "the goal is to be the first to have a winning number at the roulette" and I could try 50 times before you started, obviously I would be more likely to win our game, wouldn't I?
> In a lottery, the more tickets you buy, the higher your chances to have the winning number.
Yes, and it's exactly the same in bitcoin with the hashing power. Each hash is a ticket.
> If we played with a roulette and said "the goal is to be the first to have a winning number at the roulette" and I can try 50 times before you start, obviously I am more likely to win our game, am I not?
In bitcoin the goal is not to be the first. The goal is to find a winning hash that's on a chain that will not be abandoned. As soon as a new block is propagated you start mining on the new head. It doesn't change anything that you previously worked on another chain. The time spent on the previous chain is not wasted, unless finding a block wouldn't have got you the reward.
There is a kind of a race if 2 blocks are found simultaneously. But that's not really what this discussion is about, and in this case the outcome depends mostly on network connectivity.
It is precisely what this discussion is about. From the article:
> The key idea behind this strategy, called Selfish Mining, is for a pool to keep its discovered blocks private, thereby intentionally forking the chain. The honest nodes continue to mine on the public chain, while the pool mines on its own private branch. If the pool discovers more blocks, it develops a longer lead on the public chain, and continues to keep these new blocks private. When the public branch approaches the pool's private branch in length, the selfish miners reveal blocks from their private chain to the public.
> In bitcoin the goal is not to be the first. The goal is to find a winning hash that's on a chain that will not be abandoned.
The goal is to be the first (or very close to the first), because it makes it much more likely that your chain will not be abandoned. If you wait 2 days before you reveal your block, obviously it will be abandoned...
> The key idea behind this strategy, called Selfish Mining, is for a pool to keep its discovered blocks private, thereby intentionally forking the chain. The honest nodes continue to mine on the public chain, while the pool mines on its own private branch. If the pool discovers more blocks, it develops a longer lead on the public chain, and continues to keep these new blocks private. When the public branch approaches the pool's private branch in length, the selfish miners reveal blocks from their private chain to the public.
I don't understand how this scenario is beneficial. If the selfish miner doesn't have 51% of the hashing power, they can discover more blocks than the public chain only if they are very lucky. They don't know in advance that they will be that lucky. Withholding blocks in hope of this luck means putting these blocks at a very high risk of being discarded and losing the rewards. Why would they do that, exactly? If they get lucky, they get the rewards of their chain, and discard the rewards of the other miners. If they don't, they lose a lot of rewards. On the other hand, if they just publish the blocks they find, they're almost guaranteed to get the rewards. Why take the risk? It sounds like putting your own rewards at risk just to put others' rewards at risk. It looks like the risks even out.
> The goal is to be the first (or very close to the first), because it makes it much more likely that your chain will not be abandoned.
Yes, if there are blocks that are found at almost the same time. But that's not the situation discussed here.
In other situations, being first doesn't matter. If a miner finds a block before you do, then you just start mining on top of their block. You haven't lost anything.
> Yes, if there are blocks that are found at almost the same time. But that's not the situation discussed here.
It VERY MUCH is.
Of course if you take another scenario that doesn't make sense, then it doesn't make sense :-).
> They don't know in advance that they will be that lucky.
Whenever you find a block, you know you are one of the first to find it. It's obvious because nobody else has published a block. So you know you are lucky right now. You can decide to wait 1, 2, 5, X seconds before you reveal your block and start mining the new block in the meantime.
Maybe you just mine for 5 seconds before revealing the block, and that's the winning strategy. Maybe you wait until someone else publishes their block and you immediately reveal yours, ending up with two competing chains but knowing that you had a headstart with yours.
The detail of whether or not this is profitable, and how exactly you should do it (Wait X seconds? Wait until someone publishes a block?) is statistics and game theory ("What if the others are also withholding their blocks now? What is their strategy?"). The whole question is whether or not there is a practical, profitable strategy doing that.
But yesterday's jackpot is still running, here. If you find a block on the public chain while the other miner kept their block secret, your block becomes the main chain. If they publish their block after you, both blocks compete for the head, but it's usually the first published one that wins.
There is an advantage because occasionally you find the second block while the first block is still secret, then you release the two blocks in quick succession. That’s the edge.
What advantage does it provide vs not withholding? If you don't keep your first block secret and find a 2nd block, you get the same rewards.
On the other hand, if someone finds a block while you're keeping yours secret, it's very likely you'll lose the reward of your block.
So, you get a chance to discard the block of another miner, but you have to put your own block at risk of being discarded. Maybe there's a gain here, but it's not clear.
You can determine statistically whether you have found a block relatively early, and conversely whether other miners are unlikely to find one soon.
So you can get a head start on the next block from the likely new head block you've found.
It only works on average of course, you might be the one wasting resources if someone else published a block while you're withholding yours, but the trick is for you to gain an edge on average.
Now what happens if everyone is doing that calculation? That's where you need to do the game theory analysis (which I haven't and don't claim to understand).
> You can determine statistically whether you have found a block relatively early, and conversely whether other miners are unlikely to find one soon.
Finding a block relatively early doesn't affect the odds of others finding a block soon. The odds are always the same, each hash is an independent event.
I don't see why withholding would get you an edge on average. If the others find a block while you're withholding, you lose your reward. If you find another block before them, you get the rewards of 2 blocks, exactly like if the same happened but you didn't withhold.
The only way for you to have an advantage is if you find a 2nd block at the same time as another one finds one on the other chain. You can then publish a height of 2 vs a height of 1, so you win. But to do that you have to first put your first block reward at high risk by withholding it. I don't think the odds are in your favor here.
Yeah, I was thinking about this wrong. I don't think it works.
Edit: I think the strategy does work, but a little differently: if you withhold a block and someone else finds one while you do so, you can still publish yours and win a race with a certain probability, i.e. the expected loss is not as high as one might think.
Then, if you do that and if you have enough hash power, you can end up mining a private chain ahead of the public one often enough, so that the loss you take is less than the loss others take through the hash power they are wasting because of you doing this.
Right, but the odds of this happening is small(ish) - I'm certain there is a sweet spot for witholding time. If they don't find a block within the time interval, then effectively all the work for that time is "wasted" by the other participants since it could not have been put on the chain anyway AND the witholder has a headstart of a couple of seconds searching for a new block.
Wasting time would mean not receiving the rewards if they find a block. But that's not the case here. If they find a block within the time interval, they get the rewards (and the withheld block is discarded).
the odds depend on how much hash power you have. if you're at 5% of the network you can wait longer than if you're at 1%. the other really big problem here is it creates incentives for miners to work together to be able to delay longer
In this case A would be at an advantage to spend the 2 minutes looking for the next block. If they happen to find another block quickly they could release then in quick succession.
The benefit there is that if another miner released a block before that 3 minutes this miner still can release their first block and has already spent 2 minutes working on a block that could better validate their first block now that there are competing chains.
But the time spent by B is not wasted. If they find a block between minute 1 and 2, their block will be accepted, and A just lose the reward of the block they found.
When you reveal a block, it's not accepted instantaneously. When two competing blocks are revealed "roughly at the same time", it ends up in two competing chains.
If B finds a block between minute 1 and 2, they start working on their competing chain, but A is already working on theirs. And A had a headstart because it started working on it somewhere between minute 1. So it's more likely that A's fork wins the race in the end.
But the head start doesn't change anything. At this point A is mining on their block, B is mining on theirs. There's no advantage.
I'd even say that B is slightly more likely to keep their reward because they started propagating their block earlier, so it's more likely other miners are mining on this block.
If A finds a second block between minute 1 and 2, then they win, but it would be the same if the didn't withhold their block.
When A is mining on their hidden block, they mine for a potential height of 2 that would win against a miner only able to push a height of 1. But by doing that they put the block they found at risk of being abandoned because another miner found a block in the meantime.
So if you find a block, you get almost 100% chance it'll stay if you publish it immediately. If you withhold it and find another one you get 100% chance of keeping your 2 blocks. If you don't find that 2nd one, you get <50% chance of your block to be the main chain (depending on time of reaction of another block being published, and connectivity). On the other hand, if you don't withhold it and find 2 blocks in a row, you also get almost 100% chance of keeping your 2 blocks. I fail to see how withholding is profitable.
Because you keep ignoring the part where it is profitable :-).
> If A finds a second block between minute 1 and 2, then they win, but it would be the same if the didn't withhold their block.
Except that by withholding their block, they got a headstart so they are more likely to find the second block. So it's not the same.
And you keep ignoring the fact that they don't necessarily have to wait until someone else finds a competing block. Maybe a winning strategy is to always withhold the block for 5 seconds. If you slightly increase your likelihood to find the winning block, you increase your profit, and that's the whole point.
With the interesting consequence (and that's the game theory part) where if everybody starts withholding their block for 5 seconds, then it changes the winning strategy.
> Except that by withholding their block, they got a headstart so they are more likely to find the second block. So it's not the same.
Withholding their block (5s or whatever) doesn't make them more likely to find the second block. The probability of finding a block is always the same, given a hashrate.
They are the only ones mining on this particular chain, but that's not an advantage either. How mining on a hidden chain is an advantage?
On the other hand, withholding certainly makes them more likely to lose the reward of the block.
> They are the only ones mining on this particular chain, but that's not an advantage either. How mining on a hidden chain is an advantage?
It's easier to see the argument if you have a head start. Imagine you've somehow created a private chain that's 10 blocks ahead of the public chain. You could publish that now and earn 10 blocks of reward, or you could continue mining until the lead diminishes to 0 blocks, earning the same 10 blocks of reward plus however many blocks you've mined in the meantime.
If you have 50%+ε of the hash rate on the network, this argument would have you bully other miners out by almost always stranding their blocks, since in expectation you'll mine blocks faster than your competitors.
The insight is that this same situation can happen probabilistically with a finite but non-majority fraction of the hash rate on the network. With 49% of the hash rate you'll still be able to build a private chain some fraction of the time, so waiting a little bit to see if this occurs might have positive expected value.
But to get 10 blocks ahead you have to withhold blocks before knowing you'll be ahead. If you don't get ahead, you'll likely lose the reward of the blocks you withheld.
So, you have to risk a lot of rewards, and for what potential gain? If you win you get to discard some blocks of others. You don't get more rewards, you just make others earn less (and you push the difficulty down a bit).
I can see how you get a chance to double spend, though. If you want to double spend a transaction with N confirmations, you've to be N+1 blocks ahead in your hidden chain, publish your first transaction, wait for N confirmations on the public chain, and you publish your chain that's still 1 block ahead (and includes your double spend transaction).
Indeed, it's not "51% expensive", but it's still very expensive because of the rewards lost during the failed attempts before you get ahead enough. Actually, it might even be more expensive, because with 51% you're guaranteed to get ahead enough at some point, so you don't really risk your rewards (if you can maintain 51%).
Yes, but when you find that block you don't know whether you will be 10 blocks ahead in the future. You have to make the decision to put the reward of this block at risk before you know you'll be able apply your strategy. That's what I meant here. It is very costly on average because of the potential loss of the withheld blocks.
That's only mathematically true. The advantage is way too small to be relevant.
Your advantage is having exhausted a fraction of the search space. But that fraction is tiny.
You're trying to find a hash with a value below a certain threshold (simplified said, a hash starting with a certain amount of zeroes). You do this by trying random inputs to the hash function. Every input has the same probability of getting an output that is low enough in value. You are not advancing by having tried other inputs. It's practically equivalent to rolling multiple dices until enough of them show a one. Every roll has the same probability of succeeding regardless of the rolls before.
That's the whole question: is it relevant or not? Even if it makes mining slightly more profitable, that's a win. No need to remind you that those who mine do it exclusively for profit.
It's not. Your advancement is that of exhausting a part of the search space of SHA256 inputs for a given output. We would be in deep trouble if you made any significant advancements there or even got close to it by multiple orders of magnitude off.
> We would be in deep trouble if you made any significant advancements there
Not necessarily. The whole idea is that it maybe more profitable to withhold a block for some time. "More profitable" means that you make more money at the end. Not that you make billions in a second.
I'm not commenting on the Bitcoin economics, but on the specific problem of a partial hash inversion which Bitcoin uses. If any amount of compute you can bring up would grant you any significant amount of information about the likelihood of a (partial) hash inversion for an untested input in your search space by means of having searched a significant amount of the search space, SHA256 would be broken.
In hopefully simpler words; You want to find a hash with all zeroes. So you start trying inputs from your search space and hash them to see if they match that criterion. Every single input you try has the same probability of matching. After trying a lot of inputs you have exhausted a part of the search space. You have already tried many incorrect inputs. At some point if you keep only trying incorrect inputs you should have exhausted the whole search space and the last remaining possible input has to be the correct one resulting in an all zeroes hash. So the probability of the next hash being the correct one should go up during your search as you learn information about the remaining candidates in the search space. If this information is in any way significant in practice with any feasible amount of computing power, the cryptographic hash function is insecure. Of course with Bitcoin you aren't searching for a full hash inversion with all zeroes but only for a partial one starting with some zeroes, but that does not change the fundamentals. It should be infeasible to learn any significant information about the output of untried inputs by trying other inputs.
If SHA256 was to be broken in that way, we'd be in big trouble and Bitcoin would be the least of our worries.
the key to realize is that this strategy only makes sense if you have a considerable fraction of total hashrate. If you have 10% hashrate, delaying for 1 block period gives you a 10% chance of finding another block on top (that no one else can search for because you haven't published the first one).
But by withholding you also increase the risk that your first block will never end up in the main chain (if the remaining 90% find a block while you're withholding).
And you would sill have 10% chance of mining another block if you don't withhold.
Mining on the hidden chain is not necessarily a head start. It would be if it was certain that this hidden chain will become the main chain. But if it doesn't, then mining on it was a waste, not a head start. Of course you don't know in advance, but that's exactly my point. If you don't know whether you're on the right track, you can't say you have a head start. And in the described situation, it's not guaranteed at all that the hidden chain will become the main chain.
The hidden chain can easily be discarded if the miner of the hidden chain doesn't find a 2nd block and if the miners on the public chain find a block and propagate it before the hidden chain is published. In that case, the public chain and hidden chains will be 2 competing heads, and other miners will decide which one wins. They will generally take the first block they saw, so most likely not the (previously) hidden chain. In that situation, mining on the hidden chain was a waste, not a head start. We could even say that the miners on the public chain had a head start. That's why I say there's no such thing as a head start.
I think that at this point, you would have to learn more about probabilities. You're stuck at "I don't understand how having 51% chances to win is better than having 49%, because you cannot know the result in advance and there is a 49% chance that you lose, in which case you have lost".
> I'd even argue that the miner hiding his block is in a worse position.
That's just an intuition. You keep saying "having a headstart doesn't help, because those are independent probabilities". Which is wrong: having a headstart does help. How much does it help, and is it worth it? That's the whole question. And it would require more work to answer it.
Isn't this the same thing as saying "if everyone just agrees that a dollar bill is actually just a piece of paper, USD becomes worthless"? Albeit at a smaller scale
Fiat money has a difference: an army. It is issued by a government which has the legitimate right to demand taxes, paid in their currency, and deprive you of life and liberty if you don't.
Ultimately the populace could repudiate the whole social contract, which is also just consensus, but that's a far bigger deal than mere money.
Well to be pedantic, in the USA at least the value of the dollar is largely maintained by civilian law enforcement rather than the military. If you incur a tax liability and fail to pay your debt in US dollars then eventually the IRS will seize your assets and auction them off to settle the debt. Due to the Posse Comitatus Act, the Army doesn't get involved.
The true value of (fiat) money is derived from the fact that contracts are denominated in that money and those contracts are enforced by a central authority with guns. No other assumption is needed in financial engineering.
Hmm, maybe I wasn't following the thread very well? Many people like to discredit Bitcoin by saying it's only worth is what people decide it is. If that's not what you were trying to do then I apologize.
https://pse-info.de/en/scale/price - gold doesn't stand out, there are a few similar ones (Rhodium/Palladium/Iridium/Platinum). I haven't checked, but we'd probably find the gold price sits in a boring-looking distribution of the prices of other elements. Probably an exponential or something that could be mistaken for it. https://en.wikipedia.org/wiki/Prices_of_chemical_elements if you prefer wikipedia.
If it wasn't radioactive, poisonous and pyrophoric people would probably all just leap into the Neptunium market.
If it were only worth pennies an ounce, numerous industries wouldn't be paying what they do for it. The fact that many industries value it at several thousand dollars an ounce is self-evident from their continued use of it.
This is interesting to think about: For gold I'd say the demand is coming from both industries and from people who want it as a store of value. If it was only used as an industrial chemical, then surely the price would drop because there would be less demand.
Some bitcoin advocates will talk about how useful it is as a currency, and I wonder how much bitcoin is actually used for purposes other then to hope you can sell it to someone else for more than you paid.
If the price dropped, it would be even more in demand and reach equilibrium. Gold has several unique mechanical properties, being the most corrosion resistant metal and one of the most electrically conductive, as well as being able to be flattened into extremely thin sheets and drawn into extremely fine wire.
But that's irrelevant to the question above. The question asks "isn't [this attack] the same as saying that if everybody agrees that the USD is worthless, then it is worthless?".
The answer is "no, it's not the same". The attack does not require everybody to agree that the bitcoin is worthless.
Obviously if everybody agrees that the bitcoin is worthless, then it is worthless. But that's a separate topic.
That's a good question, but it is different. The equivalent would be "if everyone just agrees that a bitcoin is worth nothing, then it is worth nothing".
I don't know if I have a good comparison here, but maybe something like "if the bank keeps your money for a little longer before validating your transaction, they can use your money for a little longer and make more money from it". Of course if your bank says that a transaction takes 1 year, you will go to another bank. But if they say it takes a day...
Part of this post addresses the economics of creating a 6 block re-org. This makes sense as 6-confimations is the standard for Bitcoin finality today.
However, as Bitcoin's security inevitably weakens over the coming years due to diminishing miner rewards (denominated in BTC), I believe this "6-confimation" acceptance policy will change to include not only the number of confirmations, but the timing of those confirmations as well. Consider a scenario where an exchange deciding whether a tx with 6-confirmations that took 4 hours to arrive (this happens occasionally) is safe to consider finalized/settled. Even though 6-confimations may be considered safe by today's acceptance policies, this tx would still have a high probability of double spend due to the assumed 4-hour long wait for the 6 confirmations (as the attacker would have 4 hours to produce 7 blocks instead of the normal/expected 1 hour). Instead of ignoring block interarrival timing, it may make sense to include block timing as part of an acceptance policy.
So, going forward Bitcoin acceptance policies may change from today's 6-confirmation standard to something more complicated that involves the amount of time those blocks took to arrive. This would significantly enhance Bitcoin's double spending resistance without adding/altering any code and may give the network a much needed security boost in the coming years to prevent the attack discussed in the post.
If the attacker is waiting for a lucky event to occur (finding more blocks than others while having less than 51% of the mining power) it means that they are constantly wasting mining time. That in itself is a huge cost (operational cost and block rewards thrown away), but it also means that they can't predict when it will happen. A double spend attack must be planned in advance because the first transaction must occur at the beginning of the attack. I'm not sure how they could constantly try double spends without risking losing the money each time the attack doesn't happen.
I don't see how it could be profitable. If it can't be profitable, then the risk of someone doing it is pretty low. If they already have the necessary hardware, they'd be much better off mining.
> I'm not sure how they could constantly try double spends without risking losing the money each time the attack doesn't happen.
If you're not trying to profit from the double spend itself but rather from a collapse following a proven double-spend, you can double-spend the bitcoins to yourself.
"Bitcoin's security inevitably weakens over the coming years due to diminishing miner rewards (denominated in BTC)"
That's incorrect. Security scales with USD-denominated rewards, not BTC-denominated. And there are 16 years of real-world data showing they have been generally increasing, so a healthy sign that the Bitcoin experiment is working:
And not only that, but rewards are still expected to stabilize even when measured in BTC (thereby not relying on an increase of BTC's price) as they are progressively composed more and more of tx fees instead of newly mined BTC.
It's puzzling to me why some still don't understand the systemic incentives that make all this work as it has for 16 years and counting...
> It's puzzling to me why some still don't understand the systemic incentives...
Then I guess you're the type who will be really surprised to learn that with diminishing rewards comes increasing consolidation.
> ... that make all this work as it has for 16 years and counting...
That's convenient way to memory hole the market flash crashes, network forks, the blocks mined without consensus, and everything bad that happened over that timeframe.
Is a store of value that requires a significant fraction of it be eaten up by transaction fees to maintain security going to be actually useful in the long term?
With regards to transaction fees, bitcoin is already not particularly useful today. It can make sense to be used as an alternative to wire transfers where you only occasionally send a transaction, but it isn't useful as a currency and any day to day transactions have to happen off chain and not use bitcoin at all.
transaction fees are not increasing though, so they can't offset miner rewards. they have been in the $100k-$200k per day range for a long time, with only occasional breakouts: https://www.blockchain.com/explorer/charts/transaction-fees-... and the trend is not to the upside. in fact with the arrival of ETFs in 2024 the trend is clearly downwards.
Making up a bigger fraction doesn't mean that transaction fees will increase over time.
For L1 fees to actually increase over time, we need increased L1 throughput. Without that, increased demand for transactions causes more batching of transactions (mostly between exchanges).
Given the failure of BCH for pseudo-religious reasons I don't have much hope.
But transaction fees reset to zero on each block. If relying solely on transaction fees, why would you mine if they are zero? So, on the start of each block, miners will shutdown, or perhaps switch to a different currency where it would be profitable to mine. This surely weakens the security of Bitcoin.
The hashing rate is not directly relevant. That's roughly proportional to the daily dollar value of the reward times the efficiency of the leading mining hardware. The latter has gone up many orders of magnitude over the years.
> block rewards have been diminishing regularly
That's exactly what the poster you're replying to argued; the BTC denominated block subsidy halves every 4 years, and so without a corresponding doubling in price, the bitcoin security budget keeps diminishing, at least until tx fees start to dominate the subsidy.
> This would significantly enhance Bitcoin's double spending resistance without adding/altering any code
I would have expected such security rules are part of the miner code, no? Don't they need to consider rules related to the comparative security level of a chain when decided which chain to follow when multiple exist?
The answer to this problem is in the original Bitcoin whitepaper itself. It gives the formula for the required number of confirmations.
The Monero PoW community has had to deal with such nonsense, as have other smaller PoW coins.
With ε=1e-3, the expected number of 6 confirmations works only so long as the largest pool size does not exceed 12%. For a pool size of 30%, at least 24 confirmations should be required in Bitcoin, but 49 in Monero with its stricter ε=1e-6. You can see the table and the math at https://gist.github.com/impredicative/0907e1699f5ff97a9fed5d... and again it's all cleanly reproducible from the whitepaper. Anyone who is still requiring only 6 confirmations then will be setting themselves up for a risk of reversal.
TFA observes that it would be disruptive and socially difficult to move systems to expect requiring 24 confirmations, and expresses relief that other responses are possible.
Perhaps this is more suitable as a response over months or years to a long-term shift in the composition of Bitcoin miners than as a short-term measure when it appears that someone has suddenly acquired 30% of mining capacity today.
Yes: "Not aligning with reality is disruptive." Some lessons have to be learned the hard way if they're not learned the soft way. The problem is not reality.
TIL the scale of bitcoin derivatives in 2020 (hence volatility): ~2T on 2B market activity. Jeepers!
---
Starting in late 2020, as shown in The Economist's graphic, the spot market in Bitcoin became dwarfed by the derivatives markets. In the last month $1.7T of Bitcoin futures traded on unregulated exchanges, and $6.4B on regulated exchanges. Compare this with the $1.8B of the spot market in the same month.
---
Why would you expect the scale of the derivatives to be related to the scale of the spot market, especially if the derivatives are cash-settled futures? One is basically gambling on the price of BTC going up or down, and the other is trading the actual BTC, right?
Well for one with a gigantic derivatives market compared to the underlying one it becomes relatively cheap to manipulate the underlying market.
If you can make a gigantic bet on the price going up and then buy a large amount of Bitcoin that moves the price up you can win from that. See the Jane street India derivatives market issue.
I dunno, ask India and Jane Street. That's the same basic situation: when the derivative market betting on the price going up or down is much larger than the market that actually sets that price, it's ripe for arbitrage/market manipulation by a player big enough to move the market (which one you think it is depends on whether you're one of the gamblers getting fleeced or the one taking their money).
It's not really, but the difference is that I'm limited by the supply of BTC, and it requires that I actually have the money to make the 'bet' at the start. That restricts the size of the spot market.
If I'm buying futures I can enter into a contract that says "I'll buy a contract for 1BTC that says BTC is going to go from $88.5k to $98.5k in 1 year." I don't actually hand over any money. In a year's time, if BTC is now $100k the person who agreed on the contract gives me $10k. If it doesn't go up then I owe the seller $10k. The futures contract is settled in cash - no BTC is involved.
Right now though, I don't have a $88.5k to spend on BTC, so the spot market isn't an option. I probably could find $10k in a year's time so a bet on a BTC future might be viable. The actual derivative 'value' isn't real though. The only money changing hands is the delta of the change in value when the contract is settled.
(Caveat: I am a total noob at finance stuff so this could be quite wrong. One of the many reasons I will not be buying that futures contract. :) )
It's very wrong. Futures contracts on traditional exchanges have no counterparty risk and require the deposit of a significant amount of upfront capital as collateral. If the spot price of the underlying moves in either direction, debits or credits are made to and from each margin account and if you don't have the money to cover a margin call, the contract gets closed.
Margin requirements for trading spot are zero, though initial capital requirements are obviously, well, whatever spot is.
Futures contracts aren't just pieces of paper traded between people, they are actual promises to pay for physical delivery of the underlying.
It's not surprising to me that crypto people consider them nothing more than leveraged gambling slips but that's really not how one should think about them. Personally I think crypto needs far heavier regulation than it gets.
Derivatives can be structured in a time-constrained manner that requires them to go up/down in a specific time window, thus amplifying the gains/losses. Also there's generally no way to short an asset without borrowing them with a contract to pay them back (which requires timing the market move and paying rent on the asset). This is something that options contracts solved.
Its hard for me to consider owning the underlying asset as gambling compared to owning paper bets on the future value. In the former you are owning it today, in the later you are betting only on what it will cost to own later.
This is good analysis. The main longitudinal aspect omitted is that the profitability of the attack goes up as long as the price of BTC doesn't double or more each halving.
In ~6 more years, Bitcoin will undergo two more halvings, so if the price of BTC is not ~400k by then, then attack will have become more feasible.
In the near future every nation state will be vying for the largest stake of the BTC mining pie and the BTC race will be bigger than the Space Race and the Nuclear Arms Race combined and adjusted for inflation.
Only because it is being subsidized by 20 to 40 gigawatts of electricity. It is basically a ponzi scheme where the increasing difficulty transfers wealth from new comers to early adopters.
Did you read the paper? There exists a technology that has purely enforceable property rights. What is that actually worth? I don't know.
Yeah yeah, I've read the arguments about liquidity issues, shutting down the rails, making it illegal to trade, etc. but that's beside the point and depends on a thousand future variables to play out. So I don't know if btc will make it or not, but I do know property rights mean everything to humans. They literally determine whether not one is a slave (I am my own property). So just the ability to have a technology enables pure property rights to a world where nobody really has enforceable property rights over anything seems pretty interesting to me.
A 5$ wrench bar is enough to make you give me all the moneroj you have eventually. I won't know when that point is and will just continue using the wrench until I am sufficiently sure you have given me all.
> So just the ability to have a technology enables pure property rights to a world where nobody really has enforceable property rights over anything seems pretty interesting to me.
Bitcoin doesn't enforce property rights. The only thing you own is your bitcoin. The fact that I "own" my house and the land it is built on is enforced by the state with guns.
You're not getting what I'm saying. Before this technology, the concept of property rights could not be defended, depending on the attacker. This tech allows that, even if it is just for one use case.
Cars have the benefit of transporting humans and goods around.
It's more like saying a hypothetical car which moves itself by using gasoline as a propellant rather than fuel for its combustion engine would have negative value.
Sure, using fuel (of all things) for propulsion would be one way to move a vehicle, but it would be inefficient by design.
Bitcoin, at least, was created during a time where there was no alternative to security-by-inefficency, but PoS and other consensus mechanisms are pretty battle-tested now
Bitcoin has the benefit of being the first way in human history of being able to transfer value between two countries in a way that a corrupt bureaucrat, judge, or customs official can't freeze, reverse, or steal it. That's the benefit Bitcoin brings humanity, and to me, I prefer it to having a car.
Proof of Stake is an absurd security proposition. Stakeholders are immediately centralized. In every single PoS coin, the governance immediately becomes the exchanges because they always hold the most coins. They can and have used this to guide PoS coins towards governance unfavorable to the users, like as happened with Steem.
Bitcoin consumes 20 to 40GW to process 7 transactions per second. Using 30GW means about 4 billion joules per transaction. And transactions per second don't scale with more electricity. It is the least efficient technology ever created.
Scammers have ruined the forex trading market, they have deceived many people with their fake promises on high returns. I learnt my lesson the hard way. if your money has been ripped-off by these scammers, you can report to a regulated crypto investigative unit who make use of software to get money back. They helped me recover my scammed funds back to me If you encounter with some issue make sure you contact (coinhackrecovery@gmail .com) they're recovery expert and very effective .
That seems to be a reasonable position. I'm kind-of comfortable with the position of bitcoin as being large enough to attract significant attacks, but not so dominant that a catestrophic failure of the system would have significant global impact.
I have nothing against bitcoin being the money of the future, but if it is to become that, this is the sort of trial by fire that it should endure.
You will probably end up in court. But you might not get convicted.
Shakeeb Ahmed was convicted of wire fraud for exploiting a smart contract bug.
Avi Eisenberg was also convicted for exploiting a smart contract bug, but he had his conviction overturned on appeal.
The Peraire-Bueno brothers were in court for exploiting a bug in the MEV mechanism but it ended in a mis-trial so we're going to have to wait to find out.
IANAL, but from my understanding, the primary law used to prosecute hacking is the CFAA's broad "without authorization" and "exceeding authorized access" clauses.
That said, authorization implies an entity with ownership rights granting some kind of limited license to others to interact with the owner's property.
For a permissionless decentralized network with no owner, where the attack is against the consensus of which chain is valid, I'd have a hard time arguing that "authorization" as a concept is even applicable or relevant.
As wmf suggested, market manipulation laws may still apply, but I'm not sure traditional CFAA "without authorization" / "exceeding authorized access" hacking charges could apply, though I'd be willing to bet a prosecutor could make a case for wire fraud - a scheme to defraud using interstate communications.
Bitcoin is the least efficient technology ever created. There is no limit to how much electricity it can consume just to handle 7 transactions per second. No matter HOW much electricity it uses this value will never increase.
There is a limit. The cost of electricity required is bounded by the value of the reward (block reward plus transaction fees). The value of the reward is bounded too, since the "import" of electricity into the Bitcoin economy is inflationary.
This solution to this issue is extremely simple, but I bet it will never be implemented in Bitcoin BTC. That's one of the reasons why it forked in 1 August 2017.
Before the AI bubble, Bitmain was only worth ~$1 billion. Now they are worth ~15, because they make chips for AI also.
Either way, you could buy bitmain for the budget mentioned in the attack if it were for sale.
Or bitmain could pull off the attack, if indeed they do "control ... all the major mining pools" as the article alleges.
But who ultimately controls Bitmain? The Chinese state.
So, by extension, bitcoin is controlled by the CCP.
What a shitshow. Crypto needs to move on from bitcoin already, pick something better... anything better. There are so many options, and bitcoin is the worst of all of them.
Too many people have a vested interest in keeping Bitcoin going for as long as possible, sadly. It's going to take a massive black swan of some kind to shake their faith.
Heck, they can embed CSAM into the Bitcoin blockchain and that won't stop anyone from using it, because above all else, line must go up.
Like it or not in the end it will just be BTC.
China will stop exporting Bitcoin mining tech. Nation States will dump money into proprietary BTC mining tech and keep it to themselves just like military tech.
The US needs to see this reality and focus on domestic BTC mining tech like the future depends on it.
why? the easy solution is to let china monopolize bitcoin mining, and the value of bitcoin crashes. then the USD will stand unopposed and the chinese will end up with a bunch of useless equipmemt
LOL. The Sam Altman plan. Or the US could just put Bitcoin on the Entities List and forbid any US citizen and any US owned entity from investing or trading Bitcoin and Bitcoin derived financial instruments, probably force 25% or more of the Bitcoin money to pull out, crater Bitcoin value, and not perpetuate this atrocity against nature and humanity.
Well what's arguably even more horrifying is according to "Estimated average energy efficiency of bitcoin mining hardware" no significant changed happened since 2014. I imagine we went from CPU to GPU to ASIC in couple of years and now for more than a decade, no change, just more.
Well, improved energy efficiency just means more hashes/s and the difficulty adjusting. There's nothing to be gained in terms of the security or efficiency of the network as a whole by making the hardware faster, it's only good for whoever makes and uses that hardware.
You're reading the graph wrong, but I still have no idea how you are. Joules per terahash has declined from 8297 in 2014 to 33 in 2023 (the latest year they have data), a 99.996% reduction, or a 250x improvement in efficiency.
My first link shows that Bitcoin consumes roughly 40GW and my second link shows that the UK roughly does too.
There are a lot of ifs and buts here ... but the amount of power used to support the BT mechanism worldwide is roughly the same as the power consumption of the entirety of the UK.
Because every unit of electricity causes climate change and burns resources (even renewable sources of electricity - they just burn them slower). From a societal point of view we are dumping huge amounts of electricity and resources into a hole to accomplish nothing that couldn’t be accomplished with a database and a trusted third party at a billionth of the cost (or less).
The vast majority of transactions are speculation on what other people might pay for a bitcoin (i.e., a line on a spreadsheet). And even then, that speculation and trading often occurs on secondary markets which rely on trusted third parties - thus rendering the entire ordeal even more pointless.
That dreams is dead. Bitcoin is never going to be a universal digital currency. No-one (*) uses it for that purpose now, because they discovered it was rubbish as a cash system
Bitcoin cares not for how much energy it uses, just how valuable the energy it uses is. This does not make more energy available to anyone else or reduce the price.
Unless your intent isn't making the world a better place in some sort of meaningful way, learn about things and find something to care about that you can affect that actually matters. Bitcoin or AI or whatever is not worth your time. Do something real.
If we ever get to the point where bitcoin or what people are doing on servers is the most pressing problem in the world worthy of our outrage, I will cheer you on.
"Anon yells at cloud" isn't worth anyone's effort or time.
What this site does not show is how much of the power used to maintain the network is waste power such as gas that's normally burned off at the well site or hydro electric that goes to waste.
Unlike AI, there's a strong incentive to find the cheapest electricity possible. Because that's what everyone else is doing. With Bitcoin, you now exactly what your costs are and what your yields are. There's a clear threshold, when power in an area becomes too expensive there's no reason left to mine.
AI, on the other hand, is a bet on the future - infinite gains. No matter how much power costs, it's worth it to keep using as much as possible. We can't know how much power AI uses. Unlike Bitcoin, there aren't any metrics from which to extrapolate. But we do know that AI uses more power than Bitcoin already. We just have no idea how much more.
Again shenanigans. This is an arguing technique from the bitcoin maximalists who would proclaim something to be false when a google search would show otherwise.
You've drank some kind of kool-aid. You've been gaslit. Don't do it to the rest of us.
Oh I've been a decentralist long before anyone coined the term "Bitcoin Maximalist". I've been watching haters whine and complain the whole time. Speaking of google searches, you could have easily looked up the use of hyrdro power yourself and found that it's a common practice.
Speaking of, I just did a Google search asking if we know how much power AI is using and this was the AI response: "It is difficult to determine the exact amount of power AI is using because most leading AI companies do not disclose specific data"
It doesn't matter how much you hate Bitcoin, it's here and it's not going away. You should probably get over it.
> What this site does not show is how much of the power used to maintain the network is waste power such as gas that's normally burned off at the well site or hydro electric that goes to waste.
WTF? Hydro is rarely wasted because it's so dispatchable. Typically, it can only happen during high water seasons. Same for the gas power plants.
> Unlike AI, there's a strong incentive to find the cheapest electricity possible.
An interesting point is that any nation state or corporation can focus resources on either AI or BTC, but not both at the same time. BTC is a sure bet in the long run while AI is potentially capable of delivering a faster ROI with no hard guarantees. As BTC FOMO hits every country on Earth it's likely that AI will take a 100+ year backseat to massive state sponsored BTC operations. It's not hard to imagine a situation where governments restrict AI HW manufacture and limit electricity for AI as a means of supporting the national BTC effort.
And don't discount the negative sentiment around bitcoin as the nest of types that deserve to be completely wrecked financially, because they add no value to society, as in a Ponzi scheme. It seems inevitable to me this scheme is going to end some day and nobody is going to give a damn. It'll be the "Good Riddance Coin", filled with negative sentiment.
The good that BTC will do in the long run is worth the investment. Civilization getting out from under fiat currencies - once and for all - is a massive step in the right direction.
Meanwhile, Hedera remains carbon negative and 7 orders of magnitude more efficient than Bitcoin.
"Today, Hedera is performing the equivalent of over 10,000,000 transactions and 788,000 transactions for the same amount of energy it takes Bitcoin and Ethereum to process 1, respectively."
I find extremely funny that I came across this spammy comment while sitting on a vulnerability in their code because my attempts of contacting them have been unsuccessful
Top Tip: If you find the orange site's conversation on crypto to be repetitive you can change the top bar. Conversation stays the same but the colour can be changed!
Yeah, always takes me a minute when people say 'the orange site' (especially elsewhere) - it's green if I'm logged in, so I rarely see it orange, and then it's 'wuh, I'm logged out, [logs in]'.
Fortunately I'm not prone to refer to the green site.
Sanctions are just a political tool to oppress people and freedom.
The real trojan horse is the 3% inflation each year that the government subjects us to with their moneyprinting. It compounds one's savings into nothingness. That's before it ultimately blows up altogether with hyperinflation which is its only possible long-term outcome given the exponential debt that doesn't scale with GDP.
This article is FUD. No one is spending $30B+ for an attack that gasp extends the required confirmations to a few hours until a re-org can be achieved and accounts settled.
In fact, wiping out the derivative markets would be seen as a net-postive by most individual hodlers.
The Eyal & Sirer paper is pretty interesting - they basically point out that there is actually some game theory involved in when miners should reveal that they mined a block to compete most effectively with their fellows. If a pool can set up a situation where they mine a block and wait X seconds to reveal it, they can force other miners to waste X seconds of has power and gain an advantage.
It looks like a result with complex implications - eg, maybe making it impossible for new miners to set up unless they have a meaningful advantage in operating costs instead of just parity with the entrenched players. It is hard to tell because market reality is a mess but if there is a meaningful strategic choice to be made beyond simply announcing a block when it is mined then there is a lot of room for weird equilibriums even if the paper's specific analysis turns out to have flaws.
Take a look at the recently mined blocks. there are some miners that very frequently mine two blocks within quick succession, like just now for example: Block 930256: https://www.blockchain.com/explorer/blocks/btc/930256 Followed by block 930257: https://www.blockchain.com/explorer/blocks/btc/930257 The second block is usually almost empty.
This can have another explanation as well: the moment a block is found, the miner starts building on top of the previous block but hasn't constructed a new full block of transactions yet as that costs a bit of time to calculate and distribute. In this period, a new block could be found.
Blocks are Merkle trees, only the head transaction contains global seed. So, for one to mine block, one needs to walk Merkle tree up from head and then finish work with small amount of data in the block header.
Thus, the time spent mining block is directly dependent on the logarithm of number of transactions in the block.
If one can mine a block with 3000 transactions (11-12 hashes to the header) in 10 minutes, one can mine a block with one transaction (1 hash to header) about ten times as fast.
The construction of the block is negligible if we talk about complete block mining time.
This is incorrect. The miner just changes the header of the block and rehashes. The transaction set is fixed for many tries.
>If one can mine a block with 3000 transactions (11-12 hashes to the header) in 10 minutes, one can mine a block with one transaction (1 hash to header) about ten times as fast.
Huh? Surely the attempts for both take exactly the same amount of time after you've initially constructed the block, you're calculating only a single hash for each attempt.
> If a pool can set up a situation where they mine a block and wait X seconds to reveal it, they can force other miners to waste X seconds of has power and gain an advantage.
How is it wasted if they work on the current chain? If they find a block during those X seconds, they'll propagate it before the waiting pool does. The waiting pool will then just lose the revenue from the block they put on hold. They're the ones wasting mining time when that happens, while the others never do.
If you mine a block without revealing it, not only are you the only one that can mine the next block after that, but everyone is mining on the "wrong head". There's of course the risk that someone finds a different head in the meantime, but otherwise, you waste competitors' resources, while you get an advantage on the next block.
What makes it more likely that your first block ends up the next head and you're not wasting your own time on the second one if someone beats you to the first one while you're holding off?
For an arbitrary block, nothing.
It doesn't have to be arbitrary. You know when a block was "lucky" and you found it ahead of average by a given percentile. You leverage those blocks.
They are not mining on the wrong head. They are mining on the current head. If they find a block it will be accepted as the new head and the withheld block will be rejected, so it's not wasted mining time at all.
Not an expert, but I have two thoughts:
1. They don't have to wait until another miner finds a block, they can just wait "for some time" and then release their block. All that time gives them the edge for the next block.
2. My understanding is that if two different blocks are found concurrently for the same head, then the network waits for the next block to select which "new head" is accepted. I.e. when there are competing chains, the longer chain wins. So I could imagine that a strategy could be to wait until some other miner announces their block and release yours precisely at that time, hence creating two competing chains. But you presumably have an edge because you have already been mining for a while on top of your block.
There's no edge. Having spent time mining in the past doesn't increase your odds of finding a block in the future.
The idea is that you can start with the next head earlier than all the others, giving you an edge in being the first to find the next block.
But what do they gain by doing that? What's the edge? Starting earlier doesn't give you any advantage.
> Starting earlier doesn't give you any advantage
It's a race. Starting earlier obviously gives an advantage?!
No it's not a race, it's a lottery.
It would be like saying you've an edge if you start earlier at the roulette.
I think you're confused.
In a lottery, the more tickets you buy, the higher your chances to have the winning number.
If we played with a roulette and said "the goal is to be the first to have a winning number at the roulette" and I could try 50 times before you started, obviously I would be more likely to win our game, wouldn't I?
> In a lottery, the more tickets you buy, the higher your chances to have the winning number.
Yes, and it's exactly the same in bitcoin with the hashing power. Each hash is a ticket.
> If we played with a roulette and said "the goal is to be the first to have a winning number at the roulette" and I can try 50 times before you start, obviously I am more likely to win our game, am I not?
In bitcoin the goal is not to be the first. The goal is to find a winning hash that's on a chain that will not be abandoned. As soon as a new block is propagated you start mining on the new head. It doesn't change anything that you previously worked on another chain. The time spent on the previous chain is not wasted, unless finding a block wouldn't have got you the reward.
There is a kind of a race if 2 blocks are found simultaneously. But that's not really what this discussion is about, and in this case the outcome depends mostly on network connectivity.
It is precisely what this discussion is about. From the article:
> The key idea behind this strategy, called Selfish Mining, is for a pool to keep its discovered blocks private, thereby intentionally forking the chain. The honest nodes continue to mine on the public chain, while the pool mines on its own private branch. If the pool discovers more blocks, it develops a longer lead on the public chain, and continues to keep these new blocks private. When the public branch approaches the pool's private branch in length, the selfish miners reveal blocks from their private chain to the public.
> In bitcoin the goal is not to be the first. The goal is to find a winning hash that's on a chain that will not be abandoned.
The goal is to be the first (or very close to the first), because it makes it much more likely that your chain will not be abandoned. If you wait 2 days before you reveal your block, obviously it will be abandoned...
> The key idea behind this strategy, called Selfish Mining, is for a pool to keep its discovered blocks private, thereby intentionally forking the chain. The honest nodes continue to mine on the public chain, while the pool mines on its own private branch. If the pool discovers more blocks, it develops a longer lead on the public chain, and continues to keep these new blocks private. When the public branch approaches the pool's private branch in length, the selfish miners reveal blocks from their private chain to the public.
I don't understand how this scenario is beneficial. If the selfish miner doesn't have 51% of the hashing power, they can discover more blocks than the public chain only if they are very lucky. They don't know in advance that they will be that lucky. Withholding blocks in hope of this luck means putting these blocks at a very high risk of being discarded and losing the rewards. Why would they do that, exactly? If they get lucky, they get the rewards of their chain, and discard the rewards of the other miners. If they don't, they lose a lot of rewards. On the other hand, if they just publish the blocks they find, they're almost guaranteed to get the rewards. Why take the risk? It sounds like putting your own rewards at risk just to put others' rewards at risk. It looks like the risks even out.
> The goal is to be the first (or very close to the first), because it makes it much more likely that your chain will not be abandoned.
Yes, if there are blocks that are found at almost the same time. But that's not the situation discussed here.
In other situations, being first doesn't matter. If a miner finds a block before you do, then you just start mining on top of their block. You haven't lost anything.
> Yes, if there are blocks that are found at almost the same time. But that's not the situation discussed here.
It VERY MUCH is.
Of course if you take another scenario that doesn't make sense, then it doesn't make sense :-).
> They don't know in advance that they will be that lucky.
Whenever you find a block, you know you are one of the first to find it. It's obvious because nobody else has published a block. So you know you are lucky right now. You can decide to wait 1, 2, 5, X seconds before you reveal your block and start mining the new block in the meantime.
Maybe you just mine for 5 seconds before revealing the block, and that's the winning strategy. Maybe you wait until someone else publishes their block and you immediately reveal yours, ending up with two competing chains but knowing that you had a headstart with yours.
The detail of whether or not this is profitable, and how exactly you should do it (Wait X seconds? Wait until someone publishes a block?) is statistics and game theory ("What if the others are also withholding their blocks now? What is their strategy?"). The whole question is whether or not there is a practical, profitable strategy doing that.
...it's not a race, it's a lottery.
Yes, but everyone else is still buying tickets for yesterday's jackpot, while you're busy accumulating them for tomorrow's.
But yesterday's jackpot is still running, here. If you find a block on the public chain while the other miner kept their block secret, your block becomes the main chain. If they publish their block after you, both blocks compete for the head, but it's usually the first published one that wins.
There is an advantage because occasionally you find the second block while the first block is still secret, then you release the two blocks in quick succession. That’s the edge.
What advantage does it provide vs not withholding? If you don't keep your first block secret and find a 2nd block, you get the same rewards.
On the other hand, if someone finds a block while you're keeping yours secret, it's very likely you'll lose the reward of your block.
So, you get a chance to discard the block of another miner, but you have to put your own block at risk of being discarded. Maybe there's a gain here, but it's not clear.
You can determine statistically whether you have found a block relatively early, and conversely whether other miners are unlikely to find one soon.
So you can get a head start on the next block from the likely new head block you've found.
It only works on average of course, you might be the one wasting resources if someone else published a block while you're withholding yours, but the trick is for you to gain an edge on average.
Now what happens if everyone is doing that calculation? That's where you need to do the game theory analysis (which I haven't and don't claim to understand).
> You can determine statistically whether you have found a block relatively early, and conversely whether other miners are unlikely to find one soon.
Finding a block relatively early doesn't affect the odds of others finding a block soon. The odds are always the same, each hash is an independent event.
I don't see why withholding would get you an edge on average. If the others find a block while you're withholding, you lose your reward. If you find another block before them, you get the rewards of 2 blocks, exactly like if the same happened but you didn't withhold.
The only way for you to have an advantage is if you find a 2nd block at the same time as another one finds one on the other chain. You can then publish a height of 2 vs a height of 1, so you win. But to do that you have to first put your first block reward at high risk by withholding it. I don't think the odds are in your favor here.
Yeah, I was thinking about this wrong. I don't think it works.
Edit: I think the strategy does work, but a little differently: if you withhold a block and someone else finds one while you do so, you can still publish yours and win a race with a certain probability, i.e. the expected loss is not as high as one might think.
Then, if you do that and if you have enough hash power, you can end up mining a private chain ahead of the public one often enough, so that the loss you take is less than the loss others take through the hash power they are wasting because of you doing this.
Right, but the odds of this happening is small(ish) - I'm certain there is a sweet spot for witholding time. If they don't find a block within the time interval, then effectively all the work for that time is "wasted" by the other participants since it could not have been put on the chain anyway AND the witholder has a headstart of a couple of seconds searching for a new block.
Wasting time would mean not receiving the rewards if they find a block. But that's not the case here. If they find a block within the time interval, they get the rewards (and the withheld block is discarded).
the odds depend on how much hash power you have. if you're at 5% of the network you can wait longer than if you're at 1%. the other really big problem here is it creates incentives for miners to work together to be able to delay longer
I might be wrong but I think it's like this..
A finds a block after 1 minute, then powers off and waits for another minute. They reveal the block after 2 minutes.
B searches for the block for 2 minutes.
After 2 minutes, A has used 1 minute of their compute, and B has used 2.
In this case A would be at an advantage to spend the 2 minutes looking for the next block. If they happen to find another block quickly they could release then in quick succession.
The benefit there is that if another miner released a block before that 3 minutes this miner still can release their first block and has already spent 2 minutes working on a block that could better validate their first block now that there are competing chains.
But the time spent by B is not wasted. If they find a block between minute 1 and 2, their block will be accepted, and A just lose the reward of the block they found.
When you reveal a block, it's not accepted instantaneously. When two competing blocks are revealed "roughly at the same time", it ends up in two competing chains.
If B finds a block between minute 1 and 2, they start working on their competing chain, but A is already working on theirs. And A had a headstart because it started working on it somewhere between minute 1. So it's more likely that A's fork wins the race in the end.
But the head start doesn't change anything. At this point A is mining on their block, B is mining on theirs. There's no advantage.
I'd even say that B is slightly more likely to keep their reward because they started propagating their block earlier, so it's more likely other miners are mining on this block.
If A finds a second block between minute 1 and 2, then they win, but it would be the same if the didn't withhold their block.
When A is mining on their hidden block, they mine for a potential height of 2 that would win against a miner only able to push a height of 1. But by doing that they put the block they found at risk of being abandoned because another miner found a block in the meantime.
So if you find a block, you get almost 100% chance it'll stay if you publish it immediately. If you withhold it and find another one you get 100% chance of keeping your 2 blocks. If you don't find that 2nd one, you get <50% chance of your block to be the main chain (depending on time of reaction of another block being published, and connectivity). On the other hand, if you don't withhold it and find 2 blocks in a row, you also get almost 100% chance of keeping your 2 blocks. I fail to see how withholding is profitable.
> I fail to see how withholding is profitable.
Because you keep ignoring the part where it is profitable :-).
> If A finds a second block between minute 1 and 2, then they win, but it would be the same if the didn't withhold their block.
Except that by withholding their block, they got a headstart so they are more likely to find the second block. So it's not the same.
And you keep ignoring the fact that they don't necessarily have to wait until someone else finds a competing block. Maybe a winning strategy is to always withhold the block for 5 seconds. If you slightly increase your likelihood to find the winning block, you increase your profit, and that's the whole point.
With the interesting consequence (and that's the game theory part) where if everybody starts withholding their block for 5 seconds, then it changes the winning strategy.
> Except that by withholding their block, they got a headstart so they are more likely to find the second block. So it's not the same.
Withholding their block (5s or whatever) doesn't make them more likely to find the second block. The probability of finding a block is always the same, given a hashrate.
They are the only ones mining on this particular chain, but that's not an advantage either. How mining on a hidden chain is an advantage?
On the other hand, withholding certainly makes them more likely to lose the reward of the block.
> They are the only ones mining on this particular chain, but that's not an advantage either. How mining on a hidden chain is an advantage?
It's easier to see the argument if you have a head start. Imagine you've somehow created a private chain that's 10 blocks ahead of the public chain. You could publish that now and earn 10 blocks of reward, or you could continue mining until the lead diminishes to 0 blocks, earning the same 10 blocks of reward plus however many blocks you've mined in the meantime.
If you have 50%+ε of the hash rate on the network, this argument would have you bully other miners out by almost always stranding their blocks, since in expectation you'll mine blocks faster than your competitors.
The insight is that this same situation can happen probabilistically with a finite but non-majority fraction of the hash rate on the network. With 49% of the hash rate you'll still be able to build a private chain some fraction of the time, so waiting a little bit to see if this occurs might have positive expected value.
But to get 10 blocks ahead you have to withhold blocks before knowing you'll be ahead. If you don't get ahead, you'll likely lose the reward of the blocks you withheld.
So, you have to risk a lot of rewards, and for what potential gain? If you win you get to discard some blocks of others. You don't get more rewards, you just make others earn less (and you push the difficulty down a bit).
I can see how you get a chance to double spend, though. If you want to double spend a transaction with N confirmations, you've to be N+1 blocks ahead in your hidden chain, publish your first transaction, wait for N confirmations on the public chain, and you publish your chain that's still 1 block ahead (and includes your double spend transaction).
Indeed, it's not "51% expensive", but it's still very expensive because of the rewards lost during the failed attempts before you get ahead enough. Actually, it might even be more expensive, because with 51% you're guaranteed to get ahead enough at some point, so you don't really risk your rewards (if you can maintain 51%).
> But to get 10 blocks ahead you have to withhold blocks before knowing you'll be ahead.
You KNOW you are ahead, because you found a block and nobody else has published a block.
Yes, but when you find that block you don't know whether you will be 10 blocks ahead in the future. You have to make the decision to put the reward of this block at risk before you know you'll be able apply your strategy. That's what I meant here. It is very costly on average because of the potential loss of the withheld blocks.
> The probability of finding a block is always the same, given a hashrate.
I think you are missing something very basic here: the longer you compute, the higher the likelihood that you will find the hash before the others.
The extreme case being that if you can try ALL the possibilities before the others can start, then you are guarantee to find the solution before them.
That's only mathematically true. The advantage is way too small to be relevant.
Your advantage is having exhausted a fraction of the search space. But that fraction is tiny.
You're trying to find a hash with a value below a certain threshold (simplified said, a hash starting with a certain amount of zeroes). You do this by trying random inputs to the hash function. Every input has the same probability of getting an output that is low enough in value. You are not advancing by having tried other inputs. It's practically equivalent to rolling multiple dices until enough of them show a one. Every roll has the same probability of succeeding regardless of the rolls before.
> The advantage is way too small to be relevant.
That's the whole question: is it relevant or not? Even if it makes mining slightly more profitable, that's a win. No need to remind you that those who mine do it exclusively for profit.
It's not. Your advancement is that of exhausting a part of the search space of SHA256 inputs for a given output. We would be in deep trouble if you made any significant advancements there or even got close to it by multiple orders of magnitude off.
> We would be in deep trouble if you made any significant advancements there
Not necessarily. The whole idea is that it maybe more profitable to withhold a block for some time. "More profitable" means that you make more money at the end. Not that you make billions in a second.
I'm not commenting on the Bitcoin economics, but on the specific problem of a partial hash inversion which Bitcoin uses. If any amount of compute you can bring up would grant you any significant amount of information about the likelihood of a (partial) hash inversion for an untested input in your search space by means of having searched a significant amount of the search space, SHA256 would be broken.
In hopefully simpler words; You want to find a hash with all zeroes. So you start trying inputs from your search space and hash them to see if they match that criterion. Every single input you try has the same probability of matching. After trying a lot of inputs you have exhausted a part of the search space. You have already tried many incorrect inputs. At some point if you keep only trying incorrect inputs you should have exhausted the whole search space and the last remaining possible input has to be the correct one resulting in an all zeroes hash. So the probability of the next hash being the correct one should go up during your search as you learn information about the remaining candidates in the search space. If this information is in any way significant in practice with any feasible amount of computing power, the cryptographic hash function is insecure. Of course with Bitcoin you aren't searching for a full hash inversion with all zeroes but only for a partial one starting with some zeroes, but that does not change the fundamentals. It should be infeasible to learn any significant information about the output of untried inputs by trying other inputs.
If SHA256 was to be broken in that way, we'd be in big trouble and Bitcoin would be the least of our worries.
the key to realize is that this strategy only makes sense if you have a considerable fraction of total hashrate. If you have 10% hashrate, delaying for 1 block period gives you a 10% chance of finding another block on top (that no one else can search for because you haven't published the first one).
But by withholding you also increase the risk that your first block will never end up in the main chain (if the remaining 90% find a block while you're withholding).
And you would sill have 10% chance of mining another block if you don't withhold.
What advantage does withholding give you?
> What advantage does withholding give you?
One last time. By withholding, you have a headstart on the next block. If you can mine for longer, you increase your chances.
Mining on the hidden chain is not necessarily a head start. It would be if it was certain that this hidden chain will become the main chain. But if it doesn't, then mining on it was a waste, not a head start. Of course you don't know in advance, but that's exactly my point. If you don't know whether you're on the right track, you can't say you have a head start. And in the described situation, it's not guaranteed at all that the hidden chain will become the main chain.
The hidden chain can easily be discarded if the miner of the hidden chain doesn't find a 2nd block and if the miners on the public chain find a block and propagate it before the hidden chain is published. In that case, the public chain and hidden chains will be 2 competing heads, and other miners will decide which one wins. They will generally take the first block they saw, so most likely not the (previously) hidden chain. In that situation, mining on the hidden chain was a waste, not a head start. We could even say that the miners on the public chain had a head start. That's why I say there's no such thing as a head start.
I think that at this point, you would have to learn more about probabilities. You're stuck at "I don't understand how having 51% chances to win is better than having 49%, because you cannot know the result in advance and there is a 49% chance that you lose, in which case you have lost".
No, I'm saying it's not clear at all who is in a better position. I'd even argue that the miner hiding his block is in a worse position.
But I'll stop discussing that with you. It's pointless and you're way too condescending.
> I'd even argue that the miner hiding his block is in a worse position.
That's just an intuition. You keep saying "having a headstart doesn't help, because those are independent probabilities". Which is wrong: having a headstart does help. How much does it help, and is it worth it? That's the whole question. And it would require more work to answer it.
Isn't this the same thing as saying "if everyone just agrees that a dollar bill is actually just a piece of paper, USD becomes worthless"? Albeit at a smaller scale
I don't think it is the same thing. Everyone agrees that mining the next block is valuable.
Unless they didn’t.
There’s nothing inherently valuable about crypto beyond what value people assign to it in their minds.
Same with all money. Please research more before parroting this argument. You are not the first person to think of it.
Fiat money has a difference: an army. It is issued by a government which has the legitimate right to demand taxes, paid in their currency, and deprive you of life and liberty if you don't.
Ultimately the populace could repudiate the whole social contract, which is also just consensus, but that's a far bigger deal than mere money.
Well to be pedantic, in the USA at least the value of the dollar is largely maintained by civilian law enforcement rather than the military. If you incur a tax liability and fail to pay your debt in US dollars then eventually the IRS will seize your assets and auction them off to settle the debt. Due to the Posse Comitatus Act, the Army doesn't get involved.
The true value of (fiat) money is derived from the fact that contracts are denominated in that money and those contracts are enforced by a central authority with guns. No other assumption is needed in financial engineering.
GP was arguing against GGP’s point and I was simply pointing out that the argument was hollow.
What are you referring to with “research more”?
Hmm, maybe I wasn't following the thread very well? Many people like to discredit Bitcoin by saying it's only worth is what people decide it is. If that's not what you were trying to do then I apologize.
I don’t discredit any crypto based solely on its ability or inability to fulfill debts, public and private.
But I do wonder if the abstract nature of it will forever hinder its ability to do so universally.
I’m also interested why Bitcoin Cash wasn’t more successful after the fork.
>I’m also interested why Bitcoin Cash wasn’t more successful after the fork.
you mean besides it being run by a bunch of crooks and scam artists like CSW?
I wasn’t actually asking, but making a point. Thanks for helping spell it out though!
False. Gold and silver have intrinsic value beyond their use as currency.
True, but only a minuscule fraction of it is used for that purpose. If that were the sole source of its value, it would be worth pennies per once.
https://pse-info.de/en/scale/price - gold doesn't stand out, there are a few similar ones (Rhodium/Palladium/Iridium/Platinum). I haven't checked, but we'd probably find the gold price sits in a boring-looking distribution of the prices of other elements. Probably an exponential or something that could be mistaken for it. https://en.wikipedia.org/wiki/Prices_of_chemical_elements if you prefer wikipedia.
If it wasn't radioactive, poisonous and pyrophoric people would probably all just leap into the Neptunium market.
That is obviously false on it's face.
If it were only worth pennies an ounce, numerous industries wouldn't be paying what they do for it. The fact that many industries value it at several thousand dollars an ounce is self-evident from their continued use of it.
This is interesting to think about: For gold I'd say the demand is coming from both industries and from people who want it as a store of value. If it was only used as an industrial chemical, then surely the price would drop because there would be less demand.
Some bitcoin advocates will talk about how useful it is as a currency, and I wonder how much bitcoin is actually used for purposes other then to hope you can sell it to someone else for more than you paid.
If the price dropped, it would be even more in demand and reach equilibrium. Gold has several unique mechanical properties, being the most corrosion resistant metal and one of the most electrically conductive, as well as being able to be flattened into extremely thin sheets and drawn into extremely fine wire.
Not for most people. They aren't going to smelt it down and use it to build electronics or jewelry.
For most people the value is what they can receive for it in trade. Which holds for all money.
It's always hilarious when people who are unclear on the basics themselves tell other to "research more". I suppose it's the Dunning-Kruger Effect.
I don't see it that way. I see the person saying "stop making tired arguments" or "don't ask questions that have been answered hundreds of times".
But that's irrelevant to the question above. The question asks "isn't [this attack] the same as saying that if everybody agrees that the USD is worthless, then it is worthless?".
The answer is "no, it's not the same". The attack does not require everybody to agree that the bitcoin is worthless.
Obviously if everybody agrees that the bitcoin is worthless, then it is worthless. But that's a separate topic.
Okay, fine. Everyone involved** agrees that mining the next block is valuable.
That's a good question, but it is different. The equivalent would be "if everyone just agrees that a bitcoin is worth nothing, then it is worth nothing".
I don't know if I have a good comparison here, but maybe something like "if the bank keeps your money for a little longer before validating your transaction, they can use your money for a little longer and make more money from it". Of course if your bank says that a transaction takes 1 year, you will go to another bank. But if they say it takes a day...
Part of this post addresses the economics of creating a 6 block re-org. This makes sense as 6-confimations is the standard for Bitcoin finality today.
However, as Bitcoin's security inevitably weakens over the coming years due to diminishing miner rewards (denominated in BTC), I believe this "6-confimation" acceptance policy will change to include not only the number of confirmations, but the timing of those confirmations as well. Consider a scenario where an exchange deciding whether a tx with 6-confirmations that took 4 hours to arrive (this happens occasionally) is safe to consider finalized/settled. Even though 6-confimations may be considered safe by today's acceptance policies, this tx would still have a high probability of double spend due to the assumed 4-hour long wait for the 6 confirmations (as the attacker would have 4 hours to produce 7 blocks instead of the normal/expected 1 hour). Instead of ignoring block interarrival timing, it may make sense to include block timing as part of an acceptance policy.
So, going forward Bitcoin acceptance policies may change from today's 6-confirmation standard to something more complicated that involves the amount of time those blocks took to arrive. This would significantly enhance Bitcoin's double spending resistance without adding/altering any code and may give the network a much needed security boost in the coming years to prevent the attack discussed in the post.
If the attacker is waiting for a lucky event to occur (finding more blocks than others while having less than 51% of the mining power) it means that they are constantly wasting mining time. That in itself is a huge cost (operational cost and block rewards thrown away), but it also means that they can't predict when it will happen. A double spend attack must be planned in advance because the first transaction must occur at the beginning of the attack. I'm not sure how they could constantly try double spends without risking losing the money each time the attack doesn't happen.
I don't see how it could be profitable. If it can't be profitable, then the risk of someone doing it is pretty low. If they already have the necessary hardware, they'd be much better off mining.
> I'm not sure how they could constantly try double spends without risking losing the money each time the attack doesn't happen.
If you're not trying to profit from the double spend itself but rather from a collapse following a proven double-spend, you can double-spend the bitcoins to yourself.
"Bitcoin's security inevitably weakens over the coming years due to diminishing miner rewards (denominated in BTC)"
That's incorrect. Security scales with USD-denominated rewards, not BTC-denominated. And there are 16 years of real-world data showing they have been generally increasing, so a healthy sign that the Bitcoin experiment is working:
https://newhedge.io/bitcoin/block-reward-per-block
And not only that, but rewards are still expected to stabilize even when measured in BTC (thereby not relying on an increase of BTC's price) as they are progressively composed more and more of tx fees instead of newly mined BTC.
It's puzzling to me why some still don't understand the systemic incentives that make all this work as it has for 16 years and counting...
> It's puzzling to me why some still don't understand the systemic incentives...
Then I guess you're the type who will be really surprised to learn that with diminishing rewards comes increasing consolidation.
> ... that make all this work as it has for 16 years and counting...
That's convenient way to memory hole the market flash crashes, network forks, the blocks mined without consensus, and everything bad that happened over that timeframe.
How are you so confident that it will never weaken? Especially since there will come a time when the block reward is literally 0.
Tx fees make up a bigger and bigger fraction of miner rewards over time.
Is a store of value that requires a significant fraction of it be eaten up by transaction fees to maintain security going to be actually useful in the long term?
With regards to transaction fees, bitcoin is already not particularly useful today. It can make sense to be used as an alternative to wire transfers where you only occasionally send a transaction, but it isn't useful as a currency and any day to day transactions have to happen off chain and not use bitcoin at all.
Right, which is why one has to wonder who's going to want to pay enough transaction fees to secure the network.
transaction fees are not increasing though, so they can't offset miner rewards. they have been in the $100k-$200k per day range for a long time, with only occasional breakouts: https://www.blockchain.com/explorer/charts/transaction-fees-... and the trend is not to the upside. in fact with the arrival of ETFs in 2024 the trend is clearly downwards.
Making up a bigger fraction doesn't mean that transaction fees will increase over time.
For L1 fees to actually increase over time, we need increased L1 throughput. Without that, increased demand for transactions causes more batching of transactions (mostly between exchanges).
Given the failure of BCH for pseudo-religious reasons I don't have much hope.
But transaction fees reset to zero on each block. If relying solely on transaction fees, why would you mine if they are zero? So, on the start of each block, miners will shutdown, or perhaps switch to a different currency where it would be profitable to mine. This surely weakens the security of Bitcoin.
Rewards are also a permanent infinite money glitch that last in perpetuity? Or won't be changed in the future?
Rewards decrease due to halving and there is no guarantee that transaction fees will compensate it.
> However, as Bitcoin's security inevitably weakens over the coming years due to diminishing miner rewards (denominated in BTC),
Says you, without a hint of a rationale backing your argument.
It seems to me that the historical hashing rate curve tells a different story.
And block rewards have been diminishing regularly (and very predictably) pretty much since day one.
The hashing rate is not directly relevant. That's roughly proportional to the daily dollar value of the reward times the efficiency of the leading mining hardware. The latter has gone up many orders of magnitude over the years.
> block rewards have been diminishing regularly
That's exactly what the poster you're replying to argued; the BTC denominated block subsidy halves every 4 years, and so without a corresponding doubling in price, the bitcoin security budget keeps diminishing, at least until tx fees start to dominate the subsidy.
> This would significantly enhance Bitcoin's double spending resistance without adding/altering any code
I would have expected such security rules are part of the miner code, no? Don't they need to consider rules related to the comparative security level of a chain when decided which chain to follow when multiple exist?
you can accept bitcoin at any confirmation you want, it isn't a policy
in bitcoin terminology it is actually called policy rather than consensus, meaning you can choose your own config and still meet consensus rules.
The answer to this problem is in the original Bitcoin whitepaper itself. It gives the formula for the required number of confirmations.
The Monero PoW community has had to deal with such nonsense, as have other smaller PoW coins.
With ε=1e-3, the expected number of 6 confirmations works only so long as the largest pool size does not exceed 12%. For a pool size of 30%, at least 24 confirmations should be required in Bitcoin, but 49 in Monero with its stricter ε=1e-6. You can see the table and the math at https://gist.github.com/impredicative/0907e1699f5ff97a9fed5d... and again it's all cleanly reproducible from the whitepaper. Anyone who is still requiring only 6 confirmations then will be setting themselves up for a risk of reversal.
TFA observes that it would be disruptive and socially difficult to move systems to expect requiring 24 confirmations, and expresses relief that other responses are possible.
Perhaps this is more suitable as a response over months or years to a long-term shift in the composition of Bitcoin miners than as a short-term measure when it appears that someone has suddenly acquired 30% of mining capacity today.
Yes: "Not aligning with reality is disruptive." Some lessons have to be learned the hard way if they're not learned the soft way. The problem is not reality.
Bitcoin has a block/confirmation approximately every 10 minutes, and Monero every 2 minutes.
So 240 minutes for Bitcoin, and 98 minutes for Monero.
So even though Monero is more strict, it is still "faster".
TIL the scale of bitcoin derivatives in 2020 (hence volatility): ~2T on 2B market activity. Jeepers!
--- Starting in late 2020, as shown in The Economist's graphic, the spot market in Bitcoin became dwarfed by the derivatives markets. In the last month $1.7T of Bitcoin futures traded on unregulated exchanges, and $6.4B on regulated exchanges. Compare this with the $1.8B of the spot market in the same month. ---
Why would you expect the scale of the derivatives to be related to the scale of the spot market, especially if the derivatives are cash-settled futures? One is basically gambling on the price of BTC going up or down, and the other is trading the actual BTC, right?
Well for one with a gigantic derivatives market compared to the underlying one it becomes relatively cheap to manipulate the underlying market.
If you can make a gigantic bet on the price going up and then buy a large amount of Bitcoin that moves the price up you can win from that. See the Jane street India derivatives market issue.
I dunno, ask India and Jane Street. That's the same basic situation: when the derivative market betting on the price going up or down is much larger than the market that actually sets that price, it's ripe for arbitrage/market manipulation by a player big enough to move the market (which one you think it is depends on whether you're one of the gamblers getting fleeced or the one taking their money).
How is trading the actual BTC not also gambling on the price of BTC going up or down?
It's not really, but the difference is that I'm limited by the supply of BTC, and it requires that I actually have the money to make the 'bet' at the start. That restricts the size of the spot market.
If I'm buying futures I can enter into a contract that says "I'll buy a contract for 1BTC that says BTC is going to go from $88.5k to $98.5k in 1 year." I don't actually hand over any money. In a year's time, if BTC is now $100k the person who agreed on the contract gives me $10k. If it doesn't go up then I owe the seller $10k. The futures contract is settled in cash - no BTC is involved.
Right now though, I don't have a $88.5k to spend on BTC, so the spot market isn't an option. I probably could find $10k in a year's time so a bet on a BTC future might be viable. The actual derivative 'value' isn't real though. The only money changing hands is the delta of the change in value when the contract is settled.
(Caveat: I am a total noob at finance stuff so this could be quite wrong. One of the many reasons I will not be buying that futures contract. :) )
It's very wrong. Futures contracts on traditional exchanges have no counterparty risk and require the deposit of a significant amount of upfront capital as collateral. If the spot price of the underlying moves in either direction, debits or credits are made to and from each margin account and if you don't have the money to cover a margin call, the contract gets closed.
Future markets give traders leverage of 100x sometimes or more. Margin requirements are much lower than trading spot.
Margin requirements for trading spot are zero, though initial capital requirements are obviously, well, whatever spot is.
Futures contracts aren't just pieces of paper traded between people, they are actual promises to pay for physical delivery of the underlying.
It's not surprising to me that crypto people consider them nothing more than leveraged gambling slips but that's really not how one should think about them. Personally I think crypto needs far heavier regulation than it gets.
Ever heard of liquidations?
Derivatives can be structured in a time-constrained manner that requires them to go up/down in a specific time window, thus amplifying the gains/losses. Also there's generally no way to short an asset without borrowing them with a contract to pay them back (which requires timing the market move and paying rent on the asset). This is something that options contracts solved.
Its hard for me to consider owning the underlying asset as gambling compared to owning paper bets on the future value. In the former you are owning it today, in the later you are betting only on what it will cost to own later.
You might buy BTC to actually spend it, say on paying a ransomware vendor.
We’re calling these organized criminals vendors now?
Because at that scale, the tail is wagging the dog and it is not even close.
This is good analysis. The main longitudinal aspect omitted is that the profitability of the attack goes up as long as the price of BTC doesn't double or more each halving.
In ~6 more years, Bitcoin will undergo two more halvings, so if the price of BTC is not ~400k by then, then attack will have become more feasible.
In the near future every nation state will be vying for the largest stake of the BTC mining pie and the BTC race will be bigger than the Space Race and the Nuclear Arms Race combined and adjusted for inflation.
why
Why? BTC is not just worthless, it has negative value due to how much electricity it takes to securely mine new blocks.
It's worth around 85k USD at the time you wrote the comment
Only because it is being subsidized by 20 to 40 gigawatts of electricity. It is basically a ponzi scheme where the increasing difficulty transfers wealth from new comers to early adopters.
Did you read the paper? There exists a technology that has purely enforceable property rights. What is that actually worth? I don't know.
Yeah yeah, I've read the arguments about liquidity issues, shutting down the rails, making it illegal to trade, etc. but that's beside the point and depends on a thousand future variables to play out. So I don't know if btc will make it or not, but I do know property rights mean everything to humans. They literally determine whether not one is a slave (I am my own property). So just the ability to have a technology enables pure property rights to a world where nobody really has enforceable property rights over anything seems pretty interesting to me.
Property rights are enforced with guns.
That's why Monero is superior; no amount of guns is going to help somebody steal property that they don't know you have.
A 5$ wrench bar is enough to make you give me all the moneroj you have eventually. I won't know when that point is and will just continue using the wrench until I am sufficiently sure you have given me all.
So is theft. Depends on who has the most guns.
> So just the ability to have a technology enables pure property rights to a world where nobody really has enforceable property rights over anything seems pretty interesting to me.
Bitcoin doesn't enforce property rights. The only thing you own is your bitcoin. The fact that I "own" my house and the land it is built on is enforced by the state with guns.
You're not getting what I'm saying. Before this technology, the concept of property rights could not be defended, depending on the attacker. This tech allows that, even if it is just for one use case.
That's like saying cars have negative value because of how much oil it takes to run them.
Cars have the benefit of transporting humans and goods around.
It's more like saying a hypothetical car which moves itself by using gasoline as a propellant rather than fuel for its combustion engine would have negative value.
Sure, using fuel (of all things) for propulsion would be one way to move a vehicle, but it would be inefficient by design.
Bitcoin, at least, was created during a time where there was no alternative to security-by-inefficency, but PoS and other consensus mechanisms are pretty battle-tested now
Bitcoin has the benefit of being the first way in human history of being able to transfer value between two countries in a way that a corrupt bureaucrat, judge, or customs official can't freeze, reverse, or steal it. That's the benefit Bitcoin brings humanity, and to me, I prefer it to having a car.
Proof of Stake is an absurd security proposition. Stakeholders are immediately centralized. In every single PoS coin, the governance immediately becomes the exchanges because they always hold the most coins. They can and have used this to guide PoS coins towards governance unfavorable to the users, like as happened with Steem.
Bitcoin consumes 20 to 40GW to process 7 transactions per second. Using 30GW means about 4 billion joules per transaction. And transactions per second don't scale with more electricity. It is the least efficient technology ever created.
Diminishing value certainly it's called depreciation
But cars are useful.
Scammers have ruined the forex trading market, they have deceived many people with their fake promises on high returns. I learnt my lesson the hard way. if your money has been ripped-off by these scammers, you can report to a regulated crypto investigative unit who make use of software to get money back. They helped me recover my scammed funds back to me If you encounter with some issue make sure you contact (coinhackrecovery@gmail .com) they're recovery expert and very effective .
Is it illegal to attack cryptocurrency?
If crypto needs legal protection from attacks, I think that would invalidate most of its value proposition.
That seems to be a reasonable position. I'm kind-of comfortable with the position of bitcoin as being large enough to attract significant attacks, but not so dominant that a catestrophic failure of the system would have significant global impact.
I have nothing against bitcoin being the money of the future, but if it is to become that, this is the sort of trial by fire that it should endure.
Definitely reduces the cost of consensus though.
You will probably end up in court. But you might not get convicted.
Shakeeb Ahmed was convicted of wire fraud for exploiting a smart contract bug.
Avi Eisenberg was also convicted for exploiting a smart contract bug, but he had his conviction overturned on appeal.
The Peraire-Bueno brothers were in court for exploiting a bug in the MEV mechanism but it ended in a mis-trial so we're going to have to wait to find out.
Not legal advice ;-)
IANAL, but from my understanding, the primary law used to prosecute hacking is the CFAA's broad "without authorization" and "exceeding authorized access" clauses.
That said, authorization implies an entity with ownership rights granting some kind of limited license to others to interact with the owner's property.
For a permissionless decentralized network with no owner, where the attack is against the consensus of which chain is valid, I'd have a hard time arguing that "authorization" as a concept is even applicable or relevant.
As wmf suggested, market manipulation laws may still apply, but I'm not sure traditional CFAA "without authorization" / "exceeding authorized access" hacking charges could apply, though I'd be willing to bet a prosecutor could make a case for wire fraud - a scheme to defraud using interstate communications.
The attack described in this article might violate CFTC market manipulation regulations.
Depending on the currency, it's celebrated. (Code is law, etc.)
That says nothing about actual legality though, just like how me saying I am the law doesn't make me the king of the world.
Bitcoin is the least efficient technology ever created. There is no limit to how much electricity it can consume just to handle 7 transactions per second. No matter HOW much electricity it uses this value will never increase.
There is a limit. The cost of electricity required is bounded by the value of the reward (block reward plus transaction fees). The value of the reward is bounded too, since the "import" of electricity into the Bitcoin economy is inflationary.
Then making the block reward halve every 4 years is a pretty strange decision.
This solution to this issue is extremely simple, but I bet it will never be implemented in Bitcoin BTC. That's one of the reasons why it forked in 1 August 2017.
Before the AI bubble, Bitmain was only worth ~$1 billion. Now they are worth ~15, because they make chips for AI also. Either way, you could buy bitmain for the budget mentioned in the attack if it were for sale. Or bitmain could pull off the attack, if indeed they do "control ... all the major mining pools" as the article alleges.
But who ultimately controls Bitmain? The Chinese state.
So, by extension, bitcoin is controlled by the CCP.
What a shitshow. Crypto needs to move on from bitcoin already, pick something better... anything better. There are so many options, and bitcoin is the worst of all of them.
Too many people have a vested interest in keeping Bitcoin going for as long as possible, sadly. It's going to take a massive black swan of some kind to shake their faith.
Heck, they can embed CSAM into the Bitcoin blockchain and that won't stop anyone from using it, because above all else, line must go up.
Like it or not in the end it will just be BTC. China will stop exporting Bitcoin mining tech. Nation States will dump money into proprietary BTC mining tech and keep it to themselves just like military tech. The US needs to see this reality and focus on domestic BTC mining tech like the future depends on it.
why? the easy solution is to let china monopolize bitcoin mining, and the value of bitcoin crashes. then the USD will stand unopposed and the chinese will end up with a bunch of useless equipmemt
It comes down to semiconductor manufacturing, not ASIC design. Taiwan, Korea, USA are still on top.
LOL. The Sam Altman plan. Or the US could just put Bitcoin on the Entities List and forbid any US citizen and any US owned entity from investing or trading Bitcoin and Bitcoin derived financial instruments, probably force 25% or more of the Bitcoin money to pull out, crater Bitcoin value, and not perpetuate this atrocity against nature and humanity.
"Democratizing finance" my a**.
TIL: https://ccaf.io/cbnsi/cbeci - quite horrifying!
EDIT: For comparison: https://gridwatch.co.uk/
Well what's arguably even more horrifying is according to "Estimated average energy efficiency of bitcoin mining hardware" no significant changed happened since 2014. I imagine we went from CPU to GPU to ASIC in couple of years and now for more than a decade, no change, just more.
Well, improved energy efficiency just means more hashes/s and the difficulty adjusting. There's nothing to be gained in terms of the security or efficiency of the network as a whole by making the hardware faster, it's only good for whoever makes and uses that hardware.
I'm not sure what data you looking at but we went from 8300 J/TH in 2014 to 33.4 J/TH in 2023. So... what are you talking about?
They have a graph at the bottom with the name I provided "Estimated average energy efficiency of bitcoin mining hardware"
You're reading the graph wrong, but I still have no idea how you are. Joules per terahash has declined from 8297 in 2014 to 33 in 2023 (the latest year they have data), a 99.996% reduction, or a 250x improvement in efficiency.
Since when is incentivizing low cost renewable energy horrifying?
My first link shows that Bitcoin consumes roughly 40GW and my second link shows that the UK roughly does too.
There are a lot of ifs and buts here ... but the amount of power used to support the BT mechanism worldwide is roughly the same as the power consumption of the entirety of the UK.
[flagged]
Because every unit of electricity causes climate change and burns resources (even renewable sources of electricity - they just burn them slower). From a societal point of view we are dumping huge amounts of electricity and resources into a hole to accomplish nothing that couldn’t be accomplished with a database and a trusted third party at a billionth of the cost (or less).
The vast majority of transactions are speculation on what other people might pay for a bitcoin (i.e., a line on a spreadsheet). And even then, that speculation and trading often occurs on secondary markets which rely on trusted third parties - thus rendering the entire ordeal even more pointless.
In the long run BTC as a universal digital global currency will be more efficient than the fiat currencies it replaces.
That dreams is dead. Bitcoin is never going to be a universal digital currency. No-one (*) uses it for that purpose now, because they discovered it was rubbish as a cash system
(*) Approaching no-one on a global scale.
You’re right. I’ll setup the database. Everyone can trust me, honest!
Better shoot down the sun then.
Bitcoin cares not for how much energy it uses, just how valuable the energy it uses is. This does not make more energy available to anyone else or reduce the price.
[flagged]
Unless your intent isn't making the world a better place in some sort of meaningful way, learn about things and find something to care about that you can affect that actually matters. Bitcoin or AI or whatever is not worth your time. Do something real.
If we ever get to the point where bitcoin or what people are doing on servers is the most pressing problem in the world worthy of our outrage, I will cheer you on.
"Anon yells at cloud" isn't worth anyone's effort or time.
Wait till you find out how much fossil fuel energy the US burns via its military to defend the dollar.
Burning firewood actually immediately releases an extensive set of carcinogens, also causing depression.
[flagged]
What this site does not show is how much of the power used to maintain the network is waste power such as gas that's normally burned off at the well site or hydro electric that goes to waste.
Unlike AI, there's a strong incentive to find the cheapest electricity possible. Because that's what everyone else is doing. With Bitcoin, you now exactly what your costs are and what your yields are. There's a clear threshold, when power in an area becomes too expensive there's no reason left to mine.
AI, on the other hand, is a bet on the future - infinite gains. No matter how much power costs, it's worth it to keep using as much as possible. We can't know how much power AI uses. Unlike Bitcoin, there aren't any metrics from which to extrapolate. But we do know that AI uses more power than Bitcoin already. We just have no idea how much more.
> We can't know how much power AI uses.
I call shenanigans on this statement. We can and most certainly can tell how much power AI is using. The upper bound is the total datacenter usage.
Might I point out this instance of Elon's company using gas powered generators to boost power at their data center:
https://www.theguardian.com/technology/2025/apr/24/elon-musk...
We have no idea what's happening in private data centers around the world.
Again shenanigans. This is an arguing technique from the bitcoin maximalists who would proclaim something to be false when a google search would show otherwise.
You've drank some kind of kool-aid. You've been gaslit. Don't do it to the rest of us.
https://www.eia.gov/todayinenergy/detail.php?id=65564#
Oh I've been a decentralist long before anyone coined the term "Bitcoin Maximalist". I've been watching haters whine and complain the whole time. Speaking of google searches, you could have easily looked up the use of hyrdro power yourself and found that it's a common practice.
Speaking of, I just did a Google search asking if we know how much power AI is using and this was the AI response: "It is difficult to determine the exact amount of power AI is using because most leading AI companies do not disclose specific data"
It doesn't matter how much you hate Bitcoin, it's here and it's not going away. You should probably get over it.
Out of curiosity, do you have an estimate on that?
> What this site does not show is how much of the power used to maintain the network is waste power such as gas that's normally burned off at the well site or hydro electric that goes to waste.
WTF? Hydro is rarely wasted because it's so dispatchable. Typically, it can only happen during high water seasons. Same for the gas power plants.
> Unlike AI, there's a strong incentive to find the cheapest electricity possible.
Like coal.
An interesting point is that any nation state or corporation can focus resources on either AI or BTC, but not both at the same time. BTC is a sure bet in the long run while AI is potentially capable of delivering a faster ROI with no hard guarantees. As BTC FOMO hits every country on Earth it's likely that AI will take a 100+ year backseat to massive state sponsored BTC operations. It's not hard to imagine a situation where governments restrict AI HW manufacture and limit electricity for AI as a means of supporting the national BTC effort.
"BTC is a sure bet in the long run "
7 transactions per second is NOT a sure bet.
At 7 TSP BTC is far more fungible than Gold.
That doesn't make any sense at all.
And don't discount the negative sentiment around bitcoin as the nest of types that deserve to be completely wrecked financially, because they add no value to society, as in a Ponzi scheme. It seems inevitable to me this scheme is going to end some day and nobody is going to give a damn. It'll be the "Good Riddance Coin", filled with negative sentiment.
> gas that's normally burned off at the well site
Funny thing about that. Civilized governments put a stop to that, by fining flare-offs to make it economical to not do that.
I hadn't heard of this. Do they just allow the gas to go into the atmosphere instead? I've always heard that's worse than burning it
Did they require the methane be captured? I thought flare-offs were done because the methane gas is something like 1000x worse than the CO2.
flare-offs are much better than releasing raw methane into the atmosphere because methane is a much worse greenhouse gas than CO2
They still do it in North Dakota
BTC enthusiasts have very creative arguments for why their currency isn’t the a complete disaster for the climate. Like pointing fingers.
The good that BTC will do in the long run is worth the investment. Civilization getting out from under fiat currencies - once and for all - is a massive step in the right direction.
I'm curious as to what's your time horizon for "in the long run". When is this transition to bitcoin going to happen?
And what does sucking up all that low cost electricity to waste on a frivolity do to the price of electricity in general?
Cmon you remember supply and demand right
Meanwhile, Hedera remains carbon negative and 7 orders of magnitude more efficient than Bitcoin.
"Today, Hedera is performing the equivalent of over 10,000,000 transactions and 788,000 transactions for the same amount of energy it takes Bitcoin and Ethereum to process 1, respectively."
[0]: https://hedera.com/blog/going-carbon-negative-at-hedera-hash... [1]: https://discovery.ucl.ac.uk/id/eprint/10160701/
I find extremely funny that I came across this spammy comment while sitting on a vulnerability in their code because my attempts of contacting them have been unsuccessful
Here you go! https://hedera.com/bug-bounty/
Everything is orders of magnitude more efficient than bitcoin.
Databases either?
[flagged]
Top Tip: If you find the orange site's conversation on crypto to be repetitive you can change the top bar. Conversation stays the same but the colour can be changed!
Readers will want to note that this delightful feature is only available to users above 251 karma, or a knack for UserCSS.
Yeah, always takes me a minute when people say 'the orange site' (especially elsewhere) - it's green if I'm logged in, so I rarely see it orange, and then it's 'wuh, I'm logged out, [logs in]'.
Fortunately I'm not prone to refer to the green site.
Wow thank you, I'm about to be on the blue site. I never knew this and really don't like the orange.
0000FF gang, unite!
[flagged]
[flagged]
[flagged]
Sanctions are just a political tool to oppress people and freedom.
The real trojan horse is the 3% inflation each year that the government subjects us to with their moneyprinting. It compounds one's savings into nothingness. That's before it ultimately blows up altogether with hyperinflation which is its only possible long-term outcome given the exponential debt that doesn't scale with GDP.
This article is FUD. No one is spending $30B+ for an attack that gasp extends the required confirmations to a few hours until a re-org can be achieved and accounts settled.
In fact, wiping out the derivative markets would be seen as a net-postive by most individual hodlers.
You forgot to do your own research and read the article.
I believe the article reached the same conclusion you did
you can wipe out Russia with thousands of nuclear bomb