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Cost of a 51% Attack for Different Cryptocurrencies
- pornel 5y agoThis is a great reminder that having an algorithm that can be secure doesn't mean it actually is. And it's kinda scary that coins that claim to have millions of dollars in market cap can be attacked for a price of a sandwich.
- belter 5y agoI wont touch anything that has the name Bitcoin, cryptocurrency, etc....With a 10 foot pole. Still, I like to keep up with events within the field. However its is stunning: Ethereum market cap $313.09 B ( yes with a B ), and you can pull off a 51% Attack for 1.5 million dollars ? Litecoin market cap $12.51 B and you can pull off a 51% Attack for 250 thousand dollars ? It seems Vitalik Buterin gives frequent interviews. Anybody aware if has been asked about this ? Can any of you with comment on the technical validity of this info. Because frankly, if this all it takes, I am tempted :-)
- amelius 5y agoShouldn't the table also list the potential profit to be made from such an attack?
- joking 5y agovery little, once you prove that an attack of those characteristics is feasible, the entire house of cards where the “value” of those coins is stored, would collapse, and you would gain nothing from it.
- KebabLove 5y agoYou are wrong. ETC got 51% attacked 3 times in a month, with no real effect on the price.
- deleted 5y ago[deleted]
- jpalomaki 5y agoMalicious actor might be able to make a profit by shorting related stocks and playing with cryptocurrency derivatives.
- usrusr 5y agoBasically this. I think the more interesting question is how it might be possible to extract value from dominating log writes in more subtle ways. If stock market HFT can be a entire industry, what might be possible by tipping the scales of transaction latency?
- nfin 5y agogood remark, as a 51% attack does does not let you do many things. An attack does not mean, that you can pull off anything. For example with most cryptocurrencies even with an 51% attack you can't change "from who", "to who" (destination) and also not the "sending amount". Requirement: - most (or enough) people do run a validating node (and not just a SPV wallet) => That is why Bitcoin proponents to insist so much on keeping the main blockchain small and therefore secure (other solutions like lightning, ... can then be level 2 built on the secure layer. But without secure layer 1, you have nothing secure to begin with / built less upon... like less decentralised but more scalable solutions)
- wmf 5y agoYou can change your own transactions which is usually the idea behind 51% attacks. You could deposit coins into an exchange then rewrite that transaction.
- nfin 5y agoyes that’s why less secure (economicly game theoric wise) blockchains need longer confirmations (of course, it is also dependent of other factors like time to produce a block), as the probability of it happening with longer confirmation times decreases
- rattlesnakedave 5y agoit’s basically impossible to sustainably 51% Bitcoin or ETH at this point. You could 51% for an hour (maybe, if you can get that hash rate from nicehash for that long, but I doubt you actually can), but what happens at the end of that hour? Would everyone simply throw their hands up, allow your double spend, and keep mining your chain? Likely not. Andreas Antonopoulos has a good take on this for Bitcoin: https://youtu.be/ncPyMUfNyVM https://youtu.be/ncPyMUfNyVM
- osigurdson 5y agoIt is interesting that it is no longer an algorithmic consensus among machines but rather a consensus among humans. Could anyone comment on how such "reversal" type discussions take place and how many actors are involved? If power is sufficiently concentrated the fact that this can occur is a bit of a concern in itself.
- TheTester 5y ago""How is the attack cost calculated? Using the prices NiceHash lists for different algorithms we are able to calculate how much it would cost to rent enough hashing power to match the current network hashing power for an hour. Nicehash does not have enough hashing power for most larger coins, so we also calculated what percentage of the needed hashing power is available from Nicehash. Note that the attack cost does not include the block rewards that the miner will receive for mining. In some cases this can be quite significant, and reduce the attack cost by up to 80%."
- ClumsyPilot 5y agoWe've had 10 years of crypto economy, and yet, to this day, there has not been a single 51% attack on any major coin. In the same time preiod we have seen mutiple hacks again banks, governments and the military. The proof is in the pudding
- lawn 5y agoThe chart is misleading for most cryptocurrencies. The "1h Attack Cost" is calculated from the rentable hashrate from NiceHash, but you should pay attention to the "NiceHash-able" column that says how much hash you can actually rent. While you'd think you could attack Ethereum for only 1.5 million dollars, you can only rent 7% of that hashrate, so you can't get the required >50% you'd need to pull of the attack.
- ProjectArcturis 5y agoCouldn't you get additional power from various cloud computing places?
- brunocvcunha 5y agoRequires machines with strong GPUs, which are probably very limited, even for big cloud providers. Also, using cloud hardware for mining is against most terms of services, and I guess they can figure out and stop it fairly quickly.
- osigurdson 5y agoEven if you cannot conveniently rent the required hardware from a provider, it still seems rather concerning that behemoths like Ethereum could be brought down rather easily with an investment of a few million dollars (especially by government actors for example). Perhaps I misunderstand the table in the article or the impact of a 51% attack however.
- Taek 5y agoIt can't, this website is crap. Getting control of enough hardware to successfully attack Ethereum is going to be a multi billion dollar ordeal, and probably take 6+ months.
- bottled_poe 5y agoThose are some big claims without a shred of supporting evidence.
- Closi 5y agoWait $8 for a coin worth $52 million? Out of interest why aren’t these attacks more common? (Not even for profit, even just for bragging rights)
- sktrdie 5y agoBecause the attack surface is low. You can only stop transactions from happening (by mining an empty blog). You can’t change the past. Hence not worth it? Unless you can make a big purchase using the coin and then change history? There are still checkpoints implemented by clients so forcing the network to go backwards might be hard. So yeah POW doesn’t give you much attack scenarios after all.
- rattlesnakedave 5y agoThis + the honest miners would just fork the chain. Your double spend would only apply on your fork. But before it even gets to that point anyone smart enough to get that much hash power up and running would realize it’s more profitable to simply honestly mine, because for a sufficiently mature coin you’ll be found out and forked off quickly.
- viraptor 5y agoIf you want to do the double-spend really badly, would people actually react in time? Is there some precedent for the reaction time? Most big services wait to 3 confirmations, so assuming you find someone accepting 1 confirmation, network has ~20min to revert to a different chain before a rollback is just not feasible. (For BTC anyway)
- rattlesnakedave 5y agoYou wouldn’t have to roll back. It would become apparent to honest miners that there is an invalid block, and the chain would split with the dishonest blocks you mined in your version of the chain, and the honest blocks mined before the 51% attack started in another. It would be a hard fork, similar to the BTC / BCH split, where the nodes not following the protocol are on their own chain doing whatever they want, and the honest nodes carry on following the protocol as usual. Edit(s): need more coffee.
- samfisher83 5y agoWhy is og bitcoin not on the list?
- saurik 5y agoYou can't rent that algorithm on the market they are calculating the spot rates for this from; you can come at this in another direction by asking "how much profit would I have to buy off of someone else to convince them to lend me their mining equipment", and we could quibble over whether that would provide more accurate results (I think it would), but I appreciate where the author of this site is coming from: this is how much it might cost to rent this much power off an existing open market for algorithms (which doesn't bother with Bitcoin as that is mined with specialized hardware and this kind of spot market doesn't apply very well).
- fastball 5y agoThat's not accurate. You can definitely buy hashing power for BTC on NiceHash[1]. Bitcoin is just SHA-256. The more likely explanation (given that this is the crypto space) is that the author is a BTC bagholder. [1] https://www.nicehash.com/my/marketplace/SHA256 https://www.nicehash.com/my/marketplace/SHA256
- ClumsyPilot 5y agoBitcoin equipment is specilaised to mining. You'd have to rent 51% of all mining eqipment for an attack, at which point you wouod destroy the value of bitcoin and make the mining eqipment you've just rented worthless. Why would anyone rent to you in that case? So you'd have to buy the equipment, which is a gradual process, would be extremely expensive and would be noticed.
- fastball 5y agoBitcoin uses a SHA-256 hash algo, you definitely don't need specialized hardware to compute SHA-256 hashes. Yes, the competitive miners have ASICs which get you many more hashes per joule, but you can definitely rent hashing power that could 51% attack BTC without renting ASICs, it would just cost you more than if you could easily rent the most competitive hardware (obviously).
- TheTester 5y ago"How is the attack cost calculated? Using the prices NiceHash lists for different algorithms we are able to calculate how much it would cost to rent enough hashing power to match the current network hashing power for an hour. Nicehash does not have enough hashing power for most larger coins, so we also calculated what percentage of the needed hashing power is available from Nicehash. Note that the attack cost does not include the block rewards that the miner will receive for mining. In some cases this can be quite significant, and reduce the attack cost by up to 80%."
- kerng 5y agoFor the upcoming POS Ethereum chain (which is still being worked on!), the current cost is around $15 billion. And that increases as more stakers get online. Vitalik Buterin just explained that a few days ago and provided that number. So I'm very sceptical of these numbers on that website or I'm not able parse what it tries to say.
- shoto_io 5y ago> which is still worked on Sounds like any other IT project!
- lvh 5y agoA very different number for a 51% attack against a completely different consensus mechanism does not seem like it should provoke skepticism. Especially since resistance against 51% attacks is a specific benefit of that new mechanism. Are you proposing that the website plops down that $15B number for a consensus mechanism that isn't even operational yet? (I think there are other things that are misleading, notably that it measures what Nicehash could do, but not all of its capacity is actually for rent at any given time.)
- gregwebs 5y agoThat’s a small sum for many nation states but good to know we only have to worry about nations or conspiracies. Do you have a link to more information about this?
- pa7x1 5y agohttps://beaconcha.in/ https://beaconcha.in/ This is the Proof of Stake Ethereum explorer. There is over 5 M ETH staked at thr moment which gives the value given above at current market prices. In truth, that's more of a lower bound because you would have to buy that same amount of ETH in the market which would raise the price. Additionally, Ethereum's PoS algorithm contains slashing penalties that are used to burn the ETH of an attacker. So a 51% attack may occur once, the attacker then gets slashed, loses his stake and the chain continues without the attacker's stake. Read further: https://cointelegraph.com/news/vitalik-buterin-reveals-why-a-51-attack-on-eth-2-0-would-not-be-fatal https://cointelegraph.com/news/vitalik-buterin-reveals-why-a...
- bcanzanella 5y agoInteresting site, but the salient data here (1hr attack rate), is scrolled way off to the right on mobile.
- osigurdson 5y agoQuestion: What are the legalities surrounding a 51% attack?
- WanderPanda 5y agoIf code is law, it should be fine but I guess the “social layer” will have something to complain
- amelius 5y agoProbably has equal status to tax evasion. Legally correct, but socially undesired.
- dathinab 5y agoSimple, a financial crime. Just because people try to be decoupled from the government doesn't mean laws don't apply to them. Also as a side not operating a mixer without taking protocol about who used it when in which way is pretty clear cut money laundering. Hence why mixers are either exchanges which take your personalities or operated as much anonymous as possible and from countries in which they believe they can avoid the law. (EDIT: Yes there probably are people which operate a mixer without such precautions, and they might end up pretty bad if a country purses money laundering charges and it doesn't even need to be their country.)
- tkfu 5y agoI see a lot of people saying that there aren't a lot of attacks that having a 51% enables. I'd like to understand that a little bit better. Are there markets where you can short-sell cryptocurrencies? If so, mightn't you be able to turn a good profit by shorting one of these smaller coins (say Quarkchain at $30/hour with a market cap of $116M), then launching a 51% attack for a week or two, in the hopes of tanking the coins value? That would only cost you $5k per week.
- matheusmoreira 5y agoWhy is Monero not on the list?
- JustResign 5y agoEither I'm missing something big, or this site is. It assumes you can rent this capacity via NiceHash, but the whole point of a 51% attack is to run _different code_ on the majority of nodes. Surely NiceHash would rent you capacity running the vanilla e.g. Ethereum code, rather than your fork? To assume otherwise basically makes NiceHash remote code execution as a service.
- wmf 5y agoYou're missing some details about how mining works. "Miners" don't produce blocks; they just do hashing; the mining pools generate the blocks. When you rent mining capacity from NiceHash you can point it to your own pool (full node) to do whatever you want.
- miduil 5y agoPrevious discussion from the posting of this site three years ago (including by the dev who built this website). Some of which covers NiceHash topic and also other problems you're going to phase when trying to do a 51% attack + profit out of it. https://news.ycombinator.com/item?id=17173051 https://news.ycombinator.com/item?id=17173051
- GhostVII 5y agoWould a 1 hour attack have any long-term effect though? Once the attack stops, won't the legitimate chain catch up to and surpass the one that contains the false transactions? If the only effect of the attack is to have some false transactions be on the dominant chain for a few hours, the damage isn't that much different than Visa being down for a few hours, so long as you are able to either detect that the attack is happening, or just always be aware you need to wait a few hours for things to fully settle.
- remram 5y agoIsn't the entire point of blockchain to automatically prove what the consensus is? If there is a fool-proof off-the-chain way to figure out which is the "legitimate" fork, what is the point of blockchain?
- GhostVII 5y agoThe legitimate fork will take over because honest nodes will reject the illegitimate one because it contains double-spends. So as long as the majority of nodes are honest it will eventually take over.
- remram 5y agoNo fork can "contain double-spend". The idea of a double-spend is to spend once in two separate forks, e.g. taking back your money and spending it again even though you have received a service or good in exchange of it already.
- GhostVII 5y agoInteresting, so basically no transactions are illegitimate they are just wiping out old ones by publishing a longer chain? In that case, could you protect yourself against an x hour attack by waiting x hours to consider a transaction confirmed?