Ethereum could afford a 51% attack on Bitcoin, and profit greatly from it

[mjdamgaard]

I wish to discuss the following attack vector, as it seems to be a major security risk for Bitcoin.

If Ethereum mounted a successful 51% attack on Bitcoin, it would likely crash the value of Bitcoin, making Ethereum the new number one cryptocurrency.

The cost of a 51% attack has been estimated to be $6–$20 billion [1]. This is only 1.3%–4.4% of Ethereum's current market cap. And it is only 0.5%–1.5% of its potential growth if Ethereum knocks down Bitcoin and conquers its full share of the cryptocurrency market.

If Ethereum's stakeholders pool their resources, they could thus easily afford a 51% attack (also known as a Goldfinger attack in this case) against Bitcoin, and could profit quite considerably from it.

In my recent preprint [2], I also discuss how the stakeholders could potentially bribe existing Bitcoin miners anonymously through smart contracts in order to make the 51% attack even more feasible.

I posted a similar topic over on AltcoinsTalks' discussion forum, and there seems to be at least partial agreement in that thread that Ethereum stakeholders could indeed afford such an attack, and that they could in theory gain from it. The main contention at this moment seems to be more about whether they would dare or not.

So I want to pose the following question to this discussion forum: What steps will Bitcoin take to mitigate this attack vector, if any?

In particular, is it realistic that Bitcoin will convert to Proof-of-Stake as well in order to prevent such a 51% attack from being profitable?

General discussion about the feasibility and severity of this "Rival Goldfinger attack vector" is also very welcome: Is it safe to invest in Bitcoin before this attack vector has been mitigated?

[1] L. Nuzzi, K. Waters, and M. Andrade, Breaking BFT: Quantifying the Cost to Attack Bitcoin and Ethereum, https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4727999.
[2] M. J. Damgaard, A severe Goldfinger attack vector on Proof-of-Work blockchains, https://www.researchgate.net/publication/382247908_A_severe_Goldfinger_attack_vector_on_Proof-of-Work_blockchains.

[franky1]

ethereum highly likely cant/wont 51% attack bitcoin, its just not economically viable/effective/beneficial

firstly
ethereum is not even a PoW algo chain. so even if current ethereum users were to collude to want to 51% attack bitcoin.. they just cant decide one day and just do it
instead they would need to sell alot of their staked coin and then buy a heck of alot of asics. and this is not a cheap thing, nor a fast thing

bitcoiners dont buy bitcoin asics just for a one day poke at hashing for sats. they instead know that their hardware investment has about a 2 year ROI meaning that ethereum stakers cant just jump in and out for a quick one day attack at low cost. they instead have to spend ALOT of their stake combined over many many individuals colluding to afford hardware which wont reap rewards anytime soon

its also worth knowing a "marketcap" is not a storage of cash waiting for people. its just mathematics of its current(just processed) market order of a 0.0x eth multiplied by coin in circulation..

if you look at the ethereum market order book, orders are not thick of millions of coin sold per second so as soon as ethereum holders start selling coin to even try to collectively gather billions of dollars to then purchase bitcoin hardware.. just the effect of a few first runners selling ethereum would crash the ethereum market and cause the market price to drop with each subsequent seller lowering the price more and causing a case that there wont be enough buyers to get them to the billions needed

but lets say they gathered billions
at this point buying hardware, waiting for delivery and then running the asics.. wont be a situation where people would all be ready to 51% within day or a month, it would take many batches of orders over many months to get enough hardware delivered meaning many users already losing value on their eth sale wont then want to wait around to collude on a decided attack day, but instead want to morally mine bitcoin for good to start recouping losses.
so over these many months. ethereum market has dropped and lost many participants(stakers) so the ethereum community dies out trying to take on bitcoin.. and then most colluders would have felt the pain of loss and would not then want to hurt their investments(now in bitcoin) to hurt bitcoin because they would then be hurting themselves AGAIN. so they will convert to ethical miners helping the bitcoin network to protect bitcoin to protect their investment in bitcoin hardware which would need 2 year to recoup

..
as for the 51% attack itself
a 51% attack cant change the code network wide just from block producing, because if they chose to follow their own protocol in their colluding group all they are effectively doing is changing THEIR edited nodes to create an altcoin. whilst the normal nodes receiving normal blocks will continue receiving normal blocks from the moral half of the network
so effectively to stay on the network all that a 51% attack can do is:
*reverse recent confirmed blocks to undo a few transactions, which is not profitable unless they recently(same hour/day max) spent ALOT of value on bitcoin and received the goods and now want to refund themselves to "double spend" that value again..
or
*they would "empty block" new blocks containing no normal transactions apart from ones they choose.. which if they dont let certain transactions through they wont be able to spend their own rewards because the services they want to exchange with wont trust them or be able to do business if the exchanges/services other transactions are being denied

[dzungmobile]

I wish to discuss the following attack vector, as it seems to be a major security risk for Bitcoin.

If Ethereum mounted a successful 51% attack on Bitcoin, it would likely crash the value of Bitcoin, making Ethereum the new number one cryptocurrency.

The cost of a 51% attack has been estimated to be $6–$20 billion [1]. This is only 1.3%–4.4% of Ethereum's current market cap. And it is only 0.5%–1.5% of its potential growth if Ethereum knocks down Bitcoin and conquers its full share of the cryptocurrency market.

The fact is Bitcoin network had biggest total hash rates back in days when Ethereum blockchain was still Proof of Work.

This site gives you some information with its archive through Wayback machine.
https://howmanyconfs.com/

Archive in 2020
https://web.archive.org/web/20200814025529/https://howmanyconfs.com/

And now Ethereum is no longer pure PoW, how do they attack Bitcoin network by shifting rigs to mine Bitcoin rather than ETH?

A thread on risk of 51% attacks with main content from Jameson Lopp's blog.
How many Bitcoin confirmations is enough?

[mjdamgaard]

@franky1, you make some very good points. In particular, it is true that the Ethereum stakeholders wouldn't just be able to buy the ASICs from one day to the other. Nor will they likely be able to bribe the existing miners unless they also pay for their ASICs as well, since these will most likely be very hard to sell after a fall of Bitcoin.

This cost is considered, however, in the referenced $6B–$20B estimate by Nuzzi et al.

I also want to contest you on the statement that Ethereum would collapse as a result of buying enough ASICs or bribing enough miners. $6B–$20B is only 1.3%–4.4% of Ethereum's market cap, so it will only require 1.3%–4.4% of all Ether in order to pay for a 51% attack. Not something that is at all likely to cause a crash of Ethereum, will you agree?

To your point about the attackers having to 'wait around to collude' (assuming that they choose to buy ASICs rather than bribe miners and buy into existing infrastructure), it is worth pointing out that they don't have to be idle as miners in that time. They can behave as honest miners right up until the attack. Also, since this will mean that rewards will become more thinly spread out, some of the actual honest miners, who aren't backed by Ethereum stakeholders, will likely fall off in that time, making it easier for the attackers to gain a majority.

And to your point about the consequences of a 51% attack, it is worth underlining that the majority of the costs of a 51% attack are from buying the equipment. The operational costs are small in comparison. Once the attackers have gained a majority (and with the backing of Ethereum's stakeholders), they will thus be able to rewrite many more than just a few blocks of the history. They could potentially steal a lot of bitcoin in doing so. And it is therefore unlikely, as far as I can see, that Bitcoin's value wouldn't be severely damaged by this. Would you agree?

[mjdamgaard]

And now Ethereum is no longer pure PoW, how do they attack Bitcoin network by shifting rigs to mine Bitcoin rather than ETH?

The fact that Ethereum is now PoS is exactly the underlying reason why it is not really vulnerable to a similar kind of attack, aimed back at itself. Feel free to disagree with me on this point: I would not mind at all discussing this further.

[HeRetiK]

If Ethereum mounted a successful 51% attack on Bitcoin, it would likely crash the value of Bitcoin, making Ethereum the new number one cryptocurrency.

Historically speaking, whenever Bitcoin crashed, it took the whole altcoin market down with it, including Ethereum. I highly doubt Ethereum would fare much better if it were the cause for such a crash (arguably, especially if it were the cause of the crash).

The cost of a 51% attack has been estimated to be $6–$20 billion [1]. This is only 1.3%–4.4% of Ethereum's current market cap. And it is only 0.5%–1.5% of its potential growth if Ethereum knocks down Bitcoin and conquers its full share of the cryptocurrency market.

The same paper estimates an attack on Ethereum to cost around $34 billion. That would be around 2.5% of Bitcoin's market cap so the "threat" kinda goes both ways.

[mjdamgaard]

If Ethereum mounted a successful 51% attack on Bitcoin, it would likely crash the value of Bitcoin, making Ethereum the new number one cryptocurrency.

Historically speaking, whenever Bitcoin crashed, it took the whole altcoin market down with it, including Ethereum. I highly doubt Ethereum would fare much better if it were the cause for such a crash (arguably, especially if it were the cause of the crash).

The cost of a 51% attack has been estimated to be $6–$20 billion [1]. This is only 1.3%–4.4% of Ethereum's current market cap. And it is only 0.5%–1.5% of its potential growth if Ethereum knocks down Bitcoin and conquers its full share of the cryptocurrency market.

The same paper estimates an attack on Ethereum to cost around $34 billion. That would be around 2.5% of Bitcoin's market cap so the "threat" kinda goes both ways.

These are two very good points.

First of all, it is true that the price of Ethereum seems to have roughly followed the price of Bitcoin in the past. However, (as User Stompix pointed out in the mentioned AltcoinsTalks thread) it is not at all impossible that Ethereum will be able to spin it as battle between 'PoS vs. PoW' (and 'Ethereum vs Bitcoin'), sort of like a 'Nokia vs Samsung' or 'Pepsi vs Coca-Cola' situation. Once the public hears that there is a contest between the two technologies, the price of the two might no longer remain correlated.

Your second point is also very valid. But first of all, if some of the Ethereum stakeholders start funding an attack, all they and other stakeholders would have to do is to in order to mitigate a reverse attack is to collectively stake a larger amount of the total Ether. And what's more, if one reads the Ethereum docs, see in particular https://ethereum.org/en/developers/docs/consensus-mechanisms/pos/#pos-and-security, it appears that the Ethereum stakeholders believe (and maybe rightfully so) that they will easily be able to revert a 51% attack, even if one happens.

[hatshepsut93]

The cost of a 51% attack has been estimated to be $6–$20 billion [1]. This is only 1.3%–4.4% of Ethereum's current market cap. And it is only 0.5%–1.5% of its potential growth if Ethereum knocks down Bitcoin and conquers its full share of the cryptocurrency market.
.

6-20M to reverse how many blocks exactly? The way PoW deterrence works is that the cost is disproportionately higher than the result of such attack. Spending such high percentage of total market cap would be viewed as a loss for Ethereum, because it means that after a couple dozens of such attacks Ethereum's value will collapse, will Bitcoin will just suffer from a temporary set back. And the practical damage of 51% attack can be mitigated by requiring more confirmations.

[leeboy]

Successfull 51% attack on btc will create so big fud wave that all crypto will be doomed. Not sure that anyone from crypto really want to do it for promoting of own project

[mjdamgaard]

The cost of a 51% attack has been estimated to be $6–$20 billion [1]. This is only 1.3%–4.4% of Ethereum's current market cap. And it is only 0.5%–1.5% of its potential growth if Ethereum knocks down Bitcoin and conquers its full share of the cryptocurrency market.

6-20M to reverse how many blocks exactly? The way PoW deterrence works is that the cost is disproportionately higher than the result of such attack. Spending such high percentage of total market cap would be viewed as a loss for Ethereum, because it means that after a couple dozens of such attacks Ethereum's value will collapse, will Bitcoin will just suffer from a temporary set back. And the practical damage of 51% attack can be mitigated by requiring more confirmations.

6–20 billion, so hundreds of blocks, really.

No, the potential gains of a 51% attack on Bitcoin is much higher than the operational costs (since the transaction volume is much greater than the mining costs). And especially if we are assuming that the value of Bitcoin will recover afterwards, as you do. Then the attackers would just be able to keep coming back for more, once they have gained a majority.

[mjdamgaard]

Successfull 51% attack on btc will create so big fud wave that all crypto will be doomed. Not sure that anyone from crypto really want to do it for promoting of own project

Well, imagine that the attack is preceded by a long argument between the Ethereum and Bitcoin communities about whether PoW is still a viable technology.

If the Ethereum stakeholders can only prove that they have enough the power and money to mount a 51% attack on Bitcoin, perhaps by showcasing a small and harmless demonstration, then they would have a pretty good argument for why investors should buy into their PoS solution instead.

At that point, all they would need to do, in my view, is to stir up tensions about whether an actual attack will happen just enough for the some of the Bitcoin stakeholders to become uneasy and start migrating to Ethereum instead.

Once this migration has started, Bitcoin's value would drop, which would then make a 51% attack even more affordable. This could thus create a positive feedback loop where more and more investors will start migrating from Bitcoin to Ethereum.

The first ones to move will earn a lot of money, just like the preexisting Ethereum stakeholders, but the last ones to move will have lost a lot.

What do you think, is this scenario pure sci-fi, or does it sound like something that could realistically happen? 

[franky1]

@franky1, you make some very good points. In particular, it is true that the Ethereum stakeholders wouldn't just be able to buy the ASICs from one day to the other. Nor will they likely be able to bribe the existing miners unless they also pay for their ASICs as well, since these will most likely be very hard to sell after a fall of Bitcoin.

This cost is considered, however, in the referenced $6B–$20B estimate by Nuzzi et al.

I also want to contest you on the statement that Ethereum would collapse as a result of buying enough ASICs or bribing enough miners. $6B–$20B is only 1.3%–4.4% of Ethereum's market cap, so it will only require 1.3%–4.4% of all Ether in order to pay for a 51% attack. Not something that is at all likely to cause a crash of Ethereum, will you agree?

you think 1-4% is not enough to crash a market.. but here is the thing.. not all coins circulating are on the market.. only a small proportion of coins crculating are on market orders so a sudden increase of coins hitting the market supply would cause change

take for instance bitcoin, there are over 19m coins in circulation.. but there are not 19 m coins on the market. most market orders are 0.0X coins per order.. so if there was a sudden period where people were colluding to sell for instance 190,000(just 1%) coin the market orders would flood with sell orders compared to the norm.. now translate that to the numbers of ethereum circulation amount and market supply and see some scenarios of then dumping 1-4% of that circulation on the market supply.. you will soon see how it affects the markets

we seen it many times in the bitcoin market when the market orders were <1btc each. but then whales created walls and orders of just 1000 coin order lumps.. it had enough impact on the markets

To your point about the attackers having to 'wait around to collude' (assuming that they choose to buy ASICs rather than bribe miners and buy into existing infrastructure), it is worth pointing out that they don't have to be idle as miners in that time. They can behave as honest miners right up until the attack. Also, since this will mean that rewards will become more thinly spread out, some of the actual honest miners, who aren't backed by Ethereum stakeholders, will likely fall off in that time, making it easier for the attackers to gain a majority.

so we agree that they would mostly want to act as honest miners until some colluded attack date when they had enough power to attack.. however they would then while running honest, realise that now they have become bitcoin investors. their own economic position is now in ROI of bitcoin. and wanting to shoot self in the foot to attack bitcoin.. would lose them income

And to your point about the consequences of a 51% attack, it is worth underlining that the majority of the costs of a 51% attack are from buying the equipment. The operational costs are small in comparison. Once the attackers have gained a majority (and with the backing of Ethereum's stakeholders), they will thus be able to rewrite many more than just a few blocks of the history. They could potentially steal a lot of bitcoin in doing so. And it is therefore unlikely, as far as I can see, that Bitcoin's value wouldn't be severely damaged by this. Would you agree?

if you play out hashrate speeds.. there is only so far they can go back and then be able to then re-hash old block heights to catch up with the honest mining pools..
..emphasis: to achieve an ability to go back x blocks and then catch up and overtake requires more then just 51%

imagine it like olympic runners (400m relay)
2 runners, one can do 100m in 10seconds. the other can do it in 9.8seconds
now if the fastest runner can just about beat the other runner each race.. how far can he run backwards before then running forwards to overtake the other runner
can the fastest runner honestly run the first 100m side by side other. then run backwards then start from the start and run the entire 400m and still beat the other, where the other only had to run 300m in the time the dishonest racer had to redo the entire 400m
think about that
the dishonest runner cant just go back as many xxxm portions and redo the race like 2km back and then overtake the other honest runner
run the math

[pawanjain]

if you look at the ethereum market order book, orders are not thick of millions of coin sold per second so as soon as ethereum holders start selling coin to even try to collectively gather billions of dollars to then purchase bitcoin hardware.. just the effect of a few first runners selling ethereum would crash the ethereum market and cause the market price to drop with each subsequent seller lowering the price more and causing a case that there wont be enough buyers to get them to the billions needed

Those are some very good points you mentioned there. If this happens, ETH price will drastically go down and we can probably see it below $1000 or may be even $100. It would be funny to watch ETH stakers collaborating such an attack only to find out that it would backfire at them.

but lets say they gathered billions
at this point buying hardware, waiting for delivery and then running the asics.. wont be a situation where people would all be ready to 51% within day or a month, it would take many batches of orders over many months to get enough hardware delivered meaning many users already losing value on their eth sale wont then want to wait around to collude on a decided attack day, but instead want to morally mine bitcoin for good to start recouping losses.
so over these many months. ethereum market has dropped and lost many participants(stakers) so the ethereum community dies out trying to take on bitcoin.. and then most colluders would have felt the pain of loss and would not then want to hurt their investments(now in bitcoin) to hurt bitcoin because they would then be hurting themselves AGAIN. so they will convert to ethical miners helping the bitcoin network to protect bitcoin to protect their investment in bitcoin hardware which would need 2 year to recoup

Lol, at least they won't get any idea to attack a blockchain now that they will be supporting the top most blockchain 

[pooya87]

it would likely crash the value of Bitcoin, making Ethereum the new number one cryptocurrency.

So far each time bitcoin had dropped, altcoins like ethereum get annihilator without recovering.
For example back in 2017 bitcoin was at $20k and ethereum at 0.15BTC then bitcoin crashed to $3k and ethereum got destroyed by dumping down to 0.01BTC.
Today bitcoin is back up to $20k and past that to almost $70k while ethereum is about 0.04BTC

The cost of a 51% attack has been estimated to be $6–$20 billion [1]. This is only 1.3%–4.4% of Ethereum's current market cap.

You can't 51% attack with money, you'll need hardware. There is no $6-$20 billion worth of hardware for sale!
You can't also pay for it with market cap, they'll need to first own that much ether then dump it to get the money which would crash the price of this shitcoin and won't give them nearly as much as tens of millions let alone billions!

And it is only 0.5%–1.5% of its potential growth if Ethereum knocks down Bitcoin and conquers its full share of the cryptocurrency market.

At the end of the day with or without bitcoin we all know that ethereum is useless. Its only utility is for junk creation (ICO, IEO, STO, NFT, etc.) that have no usages in the real world.
It also has unlimited supply and a mutable blockchain with so many security flaws.

That all means ETH has no potential for growth whatsoever even if bitcoin dies today!

easily afford a 51% attack against Bitcoin, and could profit quite considerably from it.

There is no "profit" in performing an attack because a successful attack would crash the price and the market will shut down to prevent losses by exchanges.

potentially bribe existing Bitcoin miners ~ to make the 51% attack even more feasible.

A miner is running a business and has made a significant investment. Why would a businessman kill his own business by attacking the very thing that is making them profit?

So I want to pose the following question to this discussion forum: What steps will Bitcoin take to mitigate this attack vector, if any?

The step are already taken and it is called PoW!

In particular, is it realistic that Bitcoin will convert to Proof-of-Stake as well in order to prevent such a 51% attack from being profitable?

No because PoS is a fundamentally flawed protocol that opens the way for far worse attack vectors compared to the impossible and super expensive 51% attack.

it is not at all impossible that Ethereum will be able to spin it as battle between 'PoS vs. PoW' (and 'Ethereum vs Bitcoin'),

They've already tried that with "flipenning" nonsense many years ago. They got a little hype for their shitcoin and saw a little pump that didn't last that long.
That's about it...

As I said, at the end of the day ethereum is useless in real world.

[franky1]

if you look at the ethereum market order book, orders are not thick of millions of coin sold per second so as soon as ethereum holders start selling coin to even try to collectively gather billions of dollars to then purchase bitcoin hardware.. just the effect of a few first runners selling ethereum would crash the ethereum market and cause the market price to drop with each subsequent seller lowering the price more and causing a case that there wont be enough buyers to get them to the billions needed

Those are some very good points you mentioned there. If this happens, ETH price will drastically go down and we can probably see it below $1000 or may be even $100. It would be funny to watch ETH stakers collaborating such an attack only to find out that it would backfire at them.

what people dont realise about ethereum is due to the change of ethereum years ago, they lost alot of independent market speculation. and jsut become a shadow of bitcoins arbitrage market.
in short its bitcoins doing arbitrage via eth bridges in the market that is keeping ethereums price up. even when its value(cost) had declined by 95%+
so when the stakers(locked of of the market) suddenly unlock and sell. they will affect the market more then people think

ethereum does not have much of its own independent value sentiment. its just a sheep market for bitcoin arbitraging
you can see this because the difference between its independent market discover changed to a near flat line compared to bitcoin where bitcoin took control of ethereum price discovery

look how random and independent ethereum price was before may 14th 2021
then look how calm and roughly pegged ethereums price ratio became after May 14th 2021


yes slowly ethereum is losing its price ratio peg, moving from 12eth=1btc to now 20 eth=1btc over 3+ years. but the stability difference of that may 14th 2021 is revealing that ethereum lost its independent price discovery and come somewhat pegged to bitcoin at the 12 to 20 eth per btc ratio since then.
that ratio would get hit more when ethereum stakers unstaked and went to market

[legiteum]

We've already discussed 51% attacks on Bitcoin in a few recent threads. My own scenario had a large nation-state player like China or Russia doing it.

It's worth noting that in that discussion, it was pointed out that only two companies control more that 51% of the Bitcoin hashrate. An entity controlling these two companies (either through legal/political or clandestine means) could effectively control the Bitcoin network.

The other conclusion from the threads was that Bitcoin is ultimately protected by... the US federal government. Any actor, be it private or national, would have the USA to contend with if it were to try something like this. Indeed, it is undoubtedly the threat of the US government's reprisals that probably keeps a major entity from attacking Bitcoin. (Kind of ironic, given all of the anti-government rhetoric coming from some of the Bitcoin community).

This is worth thinking about, since the one thing Bitcoin could not survive would be an attack by the US government itself, say if Trump were elected and he was told that replacing Bitcoin with his own personal currency would make him a trillionaire.

[HeRetiK]

First of all, it is true that the price of Ethereum seems to have roughly followed the price of Bitcoin in the past. However, (as User Stompix pointed out in the mentioned AltcoinsTalks thread) it is not at all impossible that Ethereum will be able to spin it as battle between 'PoS vs. PoW' (and 'Ethereum vs Bitcoin'), sort of like a 'Nokia vs Samsung' or 'Pepsi vs Coca-Cola' situation. Once the public hears that there is a contest between the two technologies, the price of the two might no longer remain correlated.

I think at this point anyone that is interested enough in crypto to be invested (or to consider investing) is already well aware of the PoW vs PoS situation.

Regardless of that it seems impossible to guess how the market would react in practice, but given that history suggests both that (1) Bitcoin crashing takes the rest of the market with it and that (2) markets react surprisingly little to 51% attacks (though those were admittedly rather minor alts) it seems like the odds are not especially in an attacker's favor -- at least in the scenario of Ethereum trying to take Bitcoin's throne by means of a 51% attack.

Your second point is also very valid. But first of all, if some of the Ethereum stakeholders start funding an attack, all they and other stakeholders would have to do is to in order to mitigate a reverse attack is to collectively stake a larger amount of the total Ether. And what's more, if one reads the Ethereum docs, see in particular https://ethereum.org/en/developers/docs/consensus-mechanisms/pos/#pos-and-security, it appears that the Ethereum stakeholders believe (and maybe rightfully so) that they will easily be able to revert a 51% attack, even if one happens.

Please note that I'm merely comparing the two cost estimates given by the paper, assuming that both cost estimates are equally reasonable and that both attack scenarios are of similar impact. Discussing the validity of these conclusions are a different matter, but would require taking a closer look at both estimates.

6-20M to reverse how many blocks exactly? The way PoW deterrence works is that the cost is disproportionately higher than the result of such attack. Spending such high percentage of total market cap would be viewed as a loss for Ethereum, because it means that after a couple dozens of such attacks Ethereum's value will collapse, will Bitcoin will just suffer from a temporary set back. And the practical damage of 51% attack can be mitigated by requiring more confirmations.

6–20 billion, so hundreds of blocks, really.

According to the paper the range of 6-20 billion would apply to an attack that lasts for one hour. So that's about 6 blocks, not hundreds.

[mjdamgaard]

you think 1–4% is not enough to crash a market.. but here is the thing.. not all coins circulating are on the market.. only a small proportion of coins crculating are on market orders so a sudden increase of coins hitting the market supply would cause change

take for instance bitcoin, there are over 19m coins in circulation.. but there are not 19 m coins on the market. most market orders are 0.0X coins per order.. so if there was a sudden period where people were colluding to sell for instance 190,000(just 1%) coin the market orders would flood with sell orders compared to the norm.. now translate that to the numbers of ethereum circulation amount and market supply and see some scenarios of then dumping 1-4% of that circulation on the market supply.. you will soon see how it affects the markets

we seen it many times in the bitcoin market when the market orders were <1btc each. but then whales created walls and orders of just 1000 coin order lumps.. it had enough impact on the markets

This seems surprising to me. According to https://bitinfocharts.com (today), the transaction volume is roughly 0.6% each day. So I have a hard time wrapping my head around the proposition that transfers of 1%-4%, potentially over several days or months, would crash Ethereum?

Also, I think the context for why these transfers happen is important, i.e. whether they happen because investors lose interest, or if they happen simply as part of making payments.

By the way, have you considered the eventuality that I describe in my preprint where the stakeholders simply locks Ether to a smart contract instead, which is then automatically pays the participating miners in case of a successful 51% attack? Here the transfers only happen once the 51% attack has already taken place.

To your other points of your reply, yes it is true that it would require more than 51% for such an attack, ideally, and it is also true that the attackers have to weigh the profits of being honest miners against the rewards of an attack. But in the end, all this is a matter of money. And if the funding Ethereum stakeholders are willing and able to part with enough, then they should be able buy the miners for their malicious cause, assuming that the miners act selfishly, of course. 

[mjdamgaard]

it would likely crash the value of Bitcoin, making Ethereum the new number one cryptocurrency.

So far each time bitcoin had dropped, altcoins like ethereum get annihilator without recovering.
For example back in 2017 bitcoin was at $20k and ethereum at 0.15BTC then bitcoin crashed to $3k and ethereum got destroyed by dumping down to 0.01BTC.
Today bitcoin is back up to $20k and past that to almost $70k while ethereum is about 0.04BTC

[...]

At the end of the day with or without bitcoin we all know that ethereum is useless. Its only utility is for junk creation (ICO, IEO, STO, NFT, etc.) that have no usages in the real world.
It also has unlimited supply and a mutable blockchain with so many security flaws.

I believe that you are vastly underestimating Ethereum. The value of Ethereum is not 4% of Bitcoin's. It is currently 32%, according to https://bitinfocharts.com.

And regarding all the supposed security flaws of Ethereum's protocol that you mention, this also shows that there are quite a lot of people who disagrees with you and believes it to be secure. However, I would love to hear more about what you believe those security to be? This sounds quite interesting.

You can't 51% attack with money, you'll need hardware. There is no $6-$20 billion worth of hardware for sale!
You can't also pay for it with market cap, they'll need to first own that much ether then dump it to get the money which would crash the price of this shitcoin and won't give them nearly as much as tens of millions let alone billions!

[...]

A miner is running a business and has made a significant investment. Why would a businessman kill his own business by attacking the very thing that is making them profit?

Yes, this is already taken into account in the estimated price of the attack.

[DaveF]

You can't 51% attack with money, you'll need hardware. There is no $6-$20 billion worth of hardware for sale!
You can't also pay for it with market cap, they'll need to first own that much ether then dump it to get the money which would crash the price of this shitcoin and won't give them nearly as much as tens of millions let alone billions!

It's WAYYYYYYY more then that.
You also need
1) Places to host said miners.
2) Power to run said miners.
3) Staff to configure & take care of said miners
4) While buying all the available hardware for months and months you need even more money since due to lack a availability prices will go up.
5) Luck, because even someone with a $200 piece of hardware can ruin your plans.
6) Spare hardware because lets face it a lot of miners are not the most reliable things out there.
7) Even more hardware since as you are obtaining this hardware and setting it up difficulty keeps going up.

And I'm sure there are even more things I and others have not thought of mentioned.

There are many easier / quicker / cheaper ways to disrupt BTC mining. They have been discussed on and off for years and yet since nobody has ever done it, it shows that it's not really viable to do.

-Dave