"Only require a fraction", but that fraction has to come from someone or a group of people. The bigger the group, the more likely it becomes public before the attack could be pulled off (defense could be prepared) and the guys literally have to liquidate somewhere between $6 billion and $18 billion while facing the risk of losing it all. I doubt there are a lot of Elon Musks who would be willing to spend $44 billion on a Twitter platform. Liquidating that amount would also hurt their remaining holdings. Then all the uncertainty whether it works out or not. War escalates, logistics gets worse and available resources for chip manufacturing decrease out of a sudden etc.
Yes, I agree that the attack is unlikely to come from just a few rich individuals, and if the attackers form a large group of people, then it is sure to reach the public, I also agree with that.
So the point here on which we might disagree is the question of whether it would hurt the attackers if their plans become publicly known or not.
You argue that:
Ok if we assume that they make the attack public (or not), and they destroy 50% of BTC's value, which is around $650 billion, what do you think would the backlash be from all the relevant authorities? What would the consequences be for the cryptocurrency ecosystem from the SEC, CFTC, politicians, all relevant authorities around the world? Do you think they would say "well, there is a currency war and that's awesome". I think they would rigorously regulate every cryptocurrency out there because they can finally pretend to have a good reason. The consequences would be devastating and there would be investigations for sure. Whether they would be justified or not, but investigations would take place. ASICs providers would be probed whether they knew that the equipment would be used for an attack or not. If really $650 billion go down the toilet and the planning is of that magnitude as you described with middlemen and an attack coordination, I am sure heads would be rolling in one way or another.
It is not unthinkable that all these institutions would try to search for the attackers and take them to court. But as far as I can see, I don't really think that they have much stake nor interest in this, first of all.
You argue that they would care about $650 billion. But it's not their $650 billion, and the Bitcoin investors knew the risk. (The risk of a 51% attack is described in the very Satoshi whitepaper.)
Second of all, I really don't think that they would have much of a case even if they tried. Besides what the aforementioned blog post says, consider this:
While the Bitcoin exchanges, mining farms, etc., are all subject to various laws (and have to do what they promise their customers), they have no control or authority over the blockchain protocol itself. No one has. This is the defining factor of what it means that the currency is 'decentralized.'
This means that anyone is actually free to declare what they think the Bitcoin protocol should be, at any moment. And the only reason why the Bitcoin protocol doesn't change so easily is due to the Nash equilibrium of the protocol, which means that as long as >50% of the miners agree on the same protocol, it will not be economically viable for any individual to start using a different protocol.
And that's it. The miners are
not in any way obligated to follow the rules of the conventional Bitcoin protocol. Sure, mining farms are bound to follow that protocol if they have advertised that they will do so to their users. But even if they have, they can (with all likelihood) easily and quickly introduce another option to mine with a different protocol.
So this means that the attackers are just as free to declare that their protocol is actually the "right" protocol, and that the "honest miners" follow an (in their eyes) out-dated protocol. And if they do, they should, as far as I know, have just as strong case against the "honest miners," as the "honest miners" (and other institutions) have against them.
With this in mind, do you then agree that the line between "attacking miners" and "honest miners" is actually not legally meaningful (except in cases where a miner has agreed to a contract), as miners are not obligated to follow a specific Bitcoin protocol? Or am I missing something major?
And if you do, do you then agree that the would-be attackers don't actually really have to hide their intentions from anyone?
Acquiring millions of ASICs through middlemen would again raise the price. The whole coordination, logistics, higher price per piece, timing, getting it from A to B. Involving a high number of middlemen would make things only worse for the attackers and I am still absolutely convinced that simultaneous orders of ASICs that amount to the hash power of a potential 51% attack would definitely not go undetected. Then. the question remains whether ASIC manufacturers would dig their own hole by destroying POW and essentially their own gold mine.
So do you think that the ASICs suppliers would make their costumers sign a contract not to use their ASICs in a 51% attack? And do you think that they will be able to ensure that willing miners can't get around those contracts?
By the way, can I ask what you think about existing miners joining the attack? (If the Ethereum stakeholders rewards them automatically via a smart contract (see my preprint), then it seems that anyone can join the attack at any time.)
(Let me get back to your other points in the same post in a little while.)