* One actor in the space appears to have done a proof of concept takeover of 51%.
* It’s not clear there was any malicious action nor intent in doing so.
* Performing something like this is definitely expensive.
* The potential impact of doing so is disputed.
* Whether or not it was achieved is also disputed
However, what has been known you some time is that the largest BitCoin miners have more power than the entire community of many alt-coins. Whether this is an issue is a matter for debate. Certainly, until now, no-one has chosen to flex like this.
> Whether this is an issue is a matter for debate.
Monero uses RandomX, which is intentionally chosen to make it difficult to accelerate using hardware that is common with other coins. It’s almost certainly not what happened here.
In Proof-of-Work the cost of the work is what keeps the network honest. If the work has value then an attacker is free to invest as many resources as I want into subverting the network. Even a failed attack can still be profitable, just less so.
In another scenario, where the works value is less then the cost you're still hoping that at no point in the future will an attacker figure out a way to do the work at a net profit.
The only way the network can be trusted is if the work has definitely now and always, 0 value.
Not littering has value. However, if I don't litter, it doesn't benefit me, and I cannot profit off of it; no matter how eco-friendly I am, I get no value from it.
because Proof-of-Work only generates value for an arbitrary, made up coin if it has no other real value.
Otherwise you're making money that way, and the value of the coin is tied to the work that you did.
until recently gold was a pretty but mostly useless metal. too heavy for practical uses, too melty for industrial uses, too soft for weapons, etc. but it didn't rust and was a good medium of exchange because it had no other real value. once it has value outside of being currency it's less useful in that capacity, since now its value is tied to how much you can get for it by utilizing it in computers, chemical reactions, etc.... same basic idea with PoW
It's worth noting that lots of projects claim to be "Proofs of Useful Work" without the academic rigor to actually prove so. The attacker of course being one of those who has failed to do so.
1. Their paper has not been accepted by any conference or journal.
2. Neither author on their paper is an academic (or practicing engineer or researcher) in the fields of computer science, economics, game theory, or cryptography (or any maths in general). The one is a C-level exec with what seems to be minimal CS experience and the other is a psychology professor. Neither author appears to have qualifications to be able to assume some level of rigor (before looking at the underlying work).
3. The paper is a bunch of text and buzzwords about AI and AGI intermixed with some academic history and some discussions on psychology. Of the 47 pages of the paper, only about 1-2 pages are semi-technical in major with an additional ~3 pages of code included to show their algorithm. There are two graphs relevant to the protocol on those 1-2 pages and neither one addresses any security aspects, instead showing it's performance at doing the "useful" part. So again to reiterate, their "academic paper" on the security of their PoUW algorithm includes no rigorous analysis of the protocol.
TLDR They aren't doing PoUW. They are doing cooperative compute with a centralised or federated coordinator dishing out rewards.
Proofs of Useful Work do actually exist and are an interesting field but they take a lot of rigor and analysis to be accepted and not immediately ripped to shreds. What the attacker claims is not even close to meeting that bar.
Since ASICs are built for mining one specific algorithm and no other, ASIC miners are invested in the survival of "their" mining algorithm.
If there are several competing coins using the same algorithm, it may be possible to incentivize ASIC miners to destroy one of them if it benefits the others, but even then it's risky.
CPUs in contrast can be used for a million different things, CPU miners are not incentivized to support any given crypto project. It's also much easier to rent large amounts of CPUs than of ASICs.
PoS is the obvious choice now that ETH has had a bit of time to run. But, I remember when they went through the switch (before ETH PoS). Doing some sort of variation on GPU memory hard mining would have been a smart choice (ethash, progpow, etc), knowing full well that ETH would eventually go PoS. It would have given all the miners something to switch to, instead of just shutting down entirely, because there wasn't anything but ghost chains.
It's mainly an argument against CPU/GPU mining. If you have invested in specialized hardware that can mine only one coin, you're strongly incentivized to protect trust in that coin. An attacker like Qubic would need to pay you a lot more than they need to pay a CPU miner.
Crypto projects succeed/fail for all kinds of reasons that are completely unrelated to de-/centralization. You'll have to be more specific about what Grin's case should teach us.
>So then, _centralize_ around an ASIC?
ASICs are commodities. For BTC (SHA-256) there are at least 8 different companies producing ASICS, and even a smaller project like KAS (kHeavyHash) has >4 competing companies. Not much centralization risk on that side, at least not for mature projects (which a hypothetical ASIC-XMR would be by now).
The main challenge for ASIC-miners is the same as for CPU- and GPU-miners: cheap electricity -- and that's not something that can easily be centralized.
I ask this not as a gotcha (I don't know the first thing about this), but rather because I'm interested: How do you know not "ever"?
Like, trivially, it's an ASIC, so I can use it to simulate a von Neumann[*] machine, hence I can use it to run whatever algorithm I want. Would that be more efficient than using a modern OoO superscalar? Almost surely not, but that doesn't mean it can't be done, just that it shouldn't be done that way.
*: I realize that the ASICs used in Bitcoin miners don't have dram access, but that isn't a general limitation of ASICs, just those ASIC 'chips' (and maybe not even those chips, just their implementations in bitcoin miners)
EDIT: Thanks to everyone who answered! For some reason, I had it in my head that the way we implement fixed function stuff in an ASIC was basically the same as a "burn once" FPGA. Brains gonna brain.
>Like, trivially, it's an ASIC, so I can use it to simulate a von Neumann[*] machine
No, that doesn't follow at all. An ASIC doesn't mean a general purpose CPU or FPGA. A chip that only knows how to do, say, video decoding is an example of ASIC. The video chip can't do bitcoin, the bitcoin chip can't do monero. They're not general purpose.
You might be confusing ASICs with FPGAs. You can't reprogram an ASIC, the algorithm is fixed at design time, and the chip built for this single purpose.
In fact, Litecoin has an optional privacy feature called MWEB, which is probably why Litecoin too got kicked off of being named on some conventional news sites.
KAS is PoW, at ~240 times the hash-rate of LTC, ~120 000 000 times the hash-rate of XMR, and 0.0007 times the hash-rate of BTC. Obviously not really comparable...
That's not at all relevant to parent post's point. BTC mining is famously centralized, and continues to get more so. It is inevitable that a manufacturer of BTC asics with access to cheap power will become large enough to control 51% of the hash. It's inevitable. It's bad system design - it makes being able to manufacture your own custom silicon table stakes to run a financial system for some reason.
BTC will have to move to a proof of stake design to survive. It's unavoidable.
That is debatable, but also besides anything else, changing to PoS means changing the tokenomics (some tail emission for staking rewards, no 21m hard cap), which means it's incredibly unlikely to happen
In the end state (after ~2140), mining rewards just come from TX fees. But true, it is possible you could just redistribute TX fees to stakers.
Post-merge ethereum is designed so that the gas fees and the staking rewards roughly cancel out on balance (so overall inflation is around zero), but they are decoupled so even if nobody is using the network you still get a staking yield
Pedantic point: monetary inflation is around zero, not necessarily price inflation (which is what people typically mean when they just say "inflation").
I think they mean the manufacturer would just keep most of the stock for themselves. Reminds me of that famous Scarface quote: "You should get high on your own supply, it's a great idea that won't end horribly."
"Performing something like this is definitely expensive"
That is false. A 51% attack is only expensive to the degree to which the hashpower required to exceed 50% is obtained at negative margins.
If an attacker can collect the total 51% or more hashpower at what would be a profitable rate despite the attack, then the attack is not "definitely expensive" - no, the attack is definitely profitable and the expense falls sorely on the minority.
Just because something is profitable doesn't mean it's not expensive, which only means it costs a lot of money.
Or, you need to spend a lot of resources to do the attack even if it's the case that you get that money back when you succeed. And the attack is not available to you if you can't front those resources (because it's expensive rather than cheap).
You can only do that on centralized exchanges, which would mean that you effectively doxx yourself by shorting. Also the exchange will most probably seize your funds before you are able to withdraw them.
You'd have to spend $30M per day in order to control 51% of XMR, and then you'd YOLO your life savings (which would have to be another couple hundred million dollars) on centralized exchanges without anyone noticing?
I was completely wrong about the cost. XMR mining rewards amount to only $150k/day.
At the height of the attack, Qubic (the company) paid people up to $3 in QUBIC for every $1 of XMR they mined through QUBIC, and they achieved around 33% of XMR's hashrate which was sufficient to mine the majority of blocks for a few hours.
If they were forced to buy back all those QUBICs they paid out, this might have cost them ~$100k/day. But thanks to the media attention it's likely that they didn't need to buy anything back and actually were able to emit more than they otherwise could have.
XMR needs to adapt -- switch to PoS, or ASICs-based POW, or a hybrid of both.
I'm not sure I'd call this risk. Risk would be "you can invest the money, but you might not get it back" however the above is referring to the "a 51% attack absolutely works but you need a shit ton of money to do it" aspect instead. This makes it capital intensive, not (necessarily) risky.
The fact that it succeeds does not mean that you get the money back (eg the price of monero could drop if that happens). You may also have miscalculated some parameters in all this or something unexpected happens (where human factor is involved). So there should always be risk involved imo. Otherwise I agree, even in a probability 1 success situation this would still not be called "cheap".
It is absolutely risky. Your facilities can burn down once the ASICs arrive and before they are turned on, or your employees simply steal them for their own uses. Heck, you can have a fire once they get powered-on, because a power cable was poorly made. You might get sent the wrong product, or you could be ghosted without a delivery.
Expensive is a better fit than capital intensive, because there are massive ongoing costs to actually perform the attack, electricity for one.
If you want to understand the risks for a project, pretend you are at arms length and are being asked to fund the project 100% up-front. You'll find a huge list of risks very soon.
This is why I didn't say it made the investment risk free, I said being capital intensive does not make something (inherently) risky. There is no such thing as an investment without risk, but how risky it is is largely orthogonal to how capital intensive it is, and the above was talking about the latter so using the term "risk" for that half is not a great correction.
Having the power to deny others to mine blocks does not mean that you can obtain the tokens from their wallets. Miners can't sign transactions on users' behalf. You can rewrite all of history but then no exchange will accept your version of it to let you exchange the tokens for fiat. Also this will almost certainly crash the price of XMR substantially. And later people will be able to fork/restore the original version. The technological side of the blockchain is only part of the consensus/trust/market/popularity. People are the other part, and people will not pay the attacker for their successful attack.
The attacker doesn't need to steal tokens. They just need to short the token while they sufficiently disrupt the network to drive down the price. They get the money and your tokens become worthless.
I was completely wrong about the cost. XMR mining rewards amount to only $150k/day.
At the height of the attack, Qubic (the company) paid people up to $3 in QUBIC for every $1 of XMR they mined through QUBIC, and they achieved around 33% of XMR's hashrate which was sufficient to mine the majority of blocks for a few hours.
If they were forced to buy back all those QUBICs they paid out, this might have cost them ~$100k/day. But thanks to the media attention it's likely that they didn't need to buy anything back and actually were able to emit more than they otherwise could have.
XMR needs to adapt -- switch to PoS, or ASICs-based POW, or a hybrid of both.
Controlling 51% of XMR costs ~$30M per day, you'd have to short a huge amount of XMR to make that worthwhile. Who would be the counter party and how would you do that anonymously?
The attack itself is unprofitable, the "profit" for Qubic is the publicity they get. (or at least that's what they're betting on)
Monero has a theoretical market cap of $4.7B USD and daily volumes >$100M USD. I wouldn't recommend taking that short position in one go but over a few days and a few exchanges I wouldn't see a problem acquiring a very large short of the token.
In all seriousness, can you explain why the "impact of doing so is disputed". In my laypersons understanding, if you control ~51% of the hashrate you can outpace everyone else in producing blocks, which means you can change (reorganize) your blockchain history which means the ledger isn't trustworthy. Right?
- The attacker can doublespend their transactions if their hashing power is high enough to create more blocks than what the recipient is waiting for. E.g. you buy a lambo, the shop waits 10 blocks after the tx is in a block and gives you the lambo, then you create a longer chain with 11 blocks to replace the other one, and don't include the original lambo tx. 51% of hashing power is enough to create new blocks, but not enough to create 11 alternative blocks. That requires more hashing power.
- The attacker can prevent other transactions from landing in a block, as long as they have majority
- But the attacker can't create fake transactions (e.g. if they only have 1k Monero, they can't create a tx with 2k Monero). Because all nodes (not only miners) still verify the transactions
- And the attacker can also not steal your money, because they don't have your private keys
In my head I kind of simplified it - if I can reorder the blocks in my history I can "reverse" a transaction, like "erase" that I bought a lambo yesterday so today I have not only the lambo, but the money that was in my account before I bought the lambo, too. But maybe me trying to over simplify and missing the forest for the trees (this is very much not my domain).
My understanding is limited. But in addition to not making transaction "not happen". It is better to make new transaction for money. As the transaction would still be valid later and could be included later. Thus "double spend".
That's the point, you can only change YOUR history. From the perspective of future merchant, that's the trivial to deal with. And for existing transactions, you'd need the value of the goods from the transactions to exceed the cost of controlling to network to be worth it. But what kind of goods that can be transferred so quickly be worth that much?
More or less, but the private chain doesn't need to contain empty blocks.
A more sophisticated attack would include all the legitimate transactions on the network except for their own transaction(s) which they're trying to double spend. That way the network isn't disrupted apart from the parties you're double spending against.
If you control 51% of the hashing power, that means you can solve more blocks than the entire rest of the network combined. Even if other nodes on the network solve a couple blocks before you, statistically, you will eventually create a longer chain of blocks and the network will switch to your chain.
But your chain has every block solved by you, giving you all the block rewards.
That's the magic of the 51% attack. You gain control of the blocks. Because that extra 1% isn't a HUGE margin, it may take a while for your chain to become the winning chain, but theoretically, it will happen.
You only mine blocks on top of your previous blocks, ignoring blocks produced by the 49%. Since you have 51%, your chain is the longest over time, so you have 100% of the mining rewards.
You can't do that with 25% (or even 40%) hashrate.
AFAIK Qubic (the company) is paying people extra to mine XMR through Qubic (if you mine $1 worth of XMR, you get $1.50 worth of QUBIC (the coin) which you can then sell). Qubic (indirectly) loses those extra $0.50. If on average the miners sell too much (more than two thirds of the rewards), then Qubic has to buy their own coins back in order to keep the price stable. Qubic bets on their coin pumping from the publicity.
* One actor in the space appears to have done a proof of concept takeover of 51%.
* It’s not clear there was any malicious action nor intent in doing so.
* Performing something like this is definitely expensive.
* The potential impact of doing so is disputed.
* Whether or not it was achieved is also disputed
However, what has been known you some time is that the largest BitCoin miners have more power than the entire community of many alt-coins. Whether this is an issue is a matter for debate. Certainly, until now, no-one has chosen to flex like this.