What's the network plan in case of a 51% attack?

[LiveFinanciallyFree]

Is there any measure in place to protect against and recover from a 51% attack by a big enough actor?

I'm specific talking about the spawn camping attack as envisioned by Vitalik Buterin here
https://vitalik.ca/general/2020/11/06/pos2020.html

In a proof of work system, if your chain gets 51% attacked, what do you even do? So far, the only response in practice has been "wait it out until the attacker gets bored". But this misses the possibility of a much more dangerous kind of attack called a spawn camping attack, where the attacker attacks the chain over and over again with the explicit goal of rendering it useless.

In a GPU-based system, there is no defense, and a persistent attacker may quite easily render a chain permanently useless (or more realistically, switches to proof of stake or proof of authority). In fact, after the first few days, the attacker's costs may become very low, as honest miners will drop out since they have no way to get rewards while the attack is going on.

In an ASIC-based system, the community can respond to the first attack, but continuing the attack from there once again becomes trivial. The community would meet the first attack by hard-forking to change the PoW algorithm, thereby "bricking" all ASICs (the attacker's and honest miners'!). But if the attacker is willing to suffer that initial expense, after that point the situation reverts to the GPU case (as there is not enough time to build and distribute ASICs for the new algorithm), and so from there the attacker can cheaply continue the spawn camp inevitably.

[1714901812]

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[1714901812]

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[RickDeckard]

I've also thought about this in the past, but I think that this kind of attack should concern investors that aim for recent coins or coins whose network isn't strong enough to prevent such an attack. To give you an example, these type of attacks have been occurring (and I believe will continue to do so) in some coins such as Ethereum Classic[1], Firo[2], BCH[3] and Verge[4].

Regarding BTC I don't see an attack of this scale being possible in the near future mainly due to two arguments:

• The amount of computing power & energy that would be needed to perform (and sustain!) an attack like this would be something huge
• Since you need to also sustain the attack with BTC you'll have to posses a vast amount of BTC in order to feed this attack for whatever time you had in mind.

If you're interest in reading more about the possiblities of a 51% attack on BTC I can point you out to a very interesting thread that I've participated into - https://bitcointalk.org/index.php?topic=5315153 . Some quick math made by o_e_l_e_o provides you with some numbers regarding the scale of resources that would be needed to create an attack such as these aimed at the BTC network:

If we take the most recent Antminer - the S19 Pro - as a benchmark, then each ASIC device will produce 110 terahashes per second for 3,250 watts of electricity. Given that 130 exahashes per second is equivalent to 130,000,000 terahashes per second, then the attacker would need to be running around 1.18 million Antminer S19 Pros. With a cost per unit of around $4,000, then the cost just for the ASICs required would be $4.7 billion, never mind the infrastructure to house, power, and cool them all, and the 3.8 million watts of electricity to keep them running.

[1] https://www.coindesk.com/ethereum-classic-suffers-second-51-attack-in-a-week
[2] https://btcmanager.com/privacy-coin-firo-51-attack/
[3] https://decrypt.co/49819/bitcoin-cash-rebels-launch-51-attack-to-destroy-bch-hard-fork
[4] https://news.bitcoin.com/privacy-coin-verge-third-51-attack-200-days-xvg-transactions-erased/

[seoincorporation]

The 51% attack is something critical for the network, as we see in the ETC blockchain someone can buy tons of coins on an exchange, withdraw and after that deposit on the exchange to buy another alt after he withdraws the second coin he can make a 51% attack and change the blocks where he deposited on the exchange, and change that transaction to another one who redirects the coins to his wallet.

The only way to undo this action is a hardfork like the one we see with DAO hack, which is the only action to do and more than 51% of the network should be agreed with the move to make it possible.

[LiveFinanciallyFree]

Vitalik's rebuttal is that the security of the network doesn't scale as fast as the growth of the network.
It's not enough for network security to scale in dollar term, it also has to scale in BTC term because the
bigger the BTC network grows the bigger its adversaries. When BTC reaches a certain price, entire
foreign government could leverage its resource to attack the network (Russia, US, China, etc...).

Has there been any development to curtail such an attack?

[DooMAD]

Why would there be a recovery plan?  I consider chains that have suffered hashrate attacks as failed projects.  I don't waste time considering what could be done to salvage them.  There's no point being sentimental about these things.  Passionate as I am about Bitcoin, I wouldn't make an exception for it.  If Bitcoin were to fail in such a fashion, I'd be out without hesitation.  I maintain confidence that we've taken every possible precaution to avoid one happening, though.

[TangentC]

Major bitcoin supporters can't bring their-selves to believe that bitcoin could ever fall to a 51% attack.
Which is why their will be no recovery plan.

However, to those not thinking that BTC is a deity.

A simple implementation of decentralized rolling checkpoints would solve the largest dangers,
Note: a rolling checkpoint is not centralized as it is nothing more than code in each client, that refuses reorgs over a coded # of blocks.
For example, bitcoin could have a rolling checkpoint of 5 blocks, thus to be safe everyone would wait for 6 blocks before considering a transaction final, this ends the threat of double-spending. Because even if the miners had 100%, they can't change a block after the checkpoint has passed.  

As far , as the 51% threat of blocking all new blocks, if a 51% attacker did this, they guarantee a change of algorithms that will brick their asics, as the bitcoin community would be forced to move to another PoW or PoS or PoA to end their threat.

Again , don't ever expect the above to be ever be implemented , unless their is a actual 51% attack that shatters their BTC belief system.

[DooMAD]

A simple implementation of decentralized rolling checkpoints would solve the largest dangers

It doesn't, though.  Checkpoints are just a lottery to randomly determine a cut-off point where some get their last transaction honoured, while others get reversed.  That doesn't solve anything.  The chain has still failed to maintain its alignment of incentives. 

[hatshepsut93]

In a proof of work system, if your chain gets 51% attacked, what do you even do? So far, the only response in practice has been "wait it out until the attacker gets bored". But this misses the possibility of a much more dangerous kind of attack called a spawn camping attack, where the attacker attacks the chain over and over again with the explicit goal of rendering it useless.

In a GPU-based system, there is no defense, and a persistent attacker may quite easily render a chain permanently useless (or more realistically, switches to proof of stake or proof of authority). In fact, after the first few days, the attacker's costs may become very low, as honest miners will drop out since they have no way to get rewards while the attack is going on.

In an ASIC-based system, the community can respond to the first attack, but continuing the attack from there once again becomes trivial. The community would meet the first attack by hard-forking to change the PoW algorithm, thereby "bricking" all ASICs (the attacker's and honest miners'!). But if the attacker is willing to suffer that initial expense, after that point the situation reverts to the GPU case (as there is not enough time to build and distribute ASICs for the new algorithm), and so from there the attacker can cheaply continue the spawn camp inevitably.

Vitalik is straight up being dishonest here, because he wants to shill for his PoS. Attacking PoW network costs hell a lot of money, and the argument that it gets cheaper is just rubbish, because if difficulty drops, then honest miners can mine again. It's actually more fitting to say that in PoS system the attacker can attack the network as much as they want, because it costs nothing to sustain the attack.

I seriously doubt there will ever be a power in this world that will be truly capable and willing to 51% attack Bitcoin.

[LiveFinanciallyFree]

Vitalik is straight up being dishonest here, because he wants to shill for his PoS. Attacking PoW network costs hell a lot of money, and the argument that it gets cheaper is just rubbish, because if difficulty drops, then honest miners can mine again. It's actually more fitting to say that in PoS system the attacker can attack the network as much as they want, because it costs nothing to sustain the attack.

I seriously doubt there will ever be a power in this world that will be truly capable and willing to 51% attack Bitcoin.

Government state can print unlimited amount of money. Beside, what if they don't even have to purchase the ASICs? They can just confiscated the mining equipment from miners (very plausible in authoritarian states like Russia or China where government has lots of power).

In PoS it's actually exponentially more expensive to sustain an attack as the stake of the attacker is destroyed. They would have to keep buying coin from a decreasing supply at an increasing price, which would tend to infinity.

[pooya87]

Again , don't ever expect the above to be ever be implemented , unless their is a actual 51% attack that shatters their BTC belief system.

This is just your opinion that impossibility of a successful sustained 51% attack is just a belief.
You are also reading the altcoin related arguments and applying them to bitcoin while there is a huge difference between the massive bitcoin network with its hashrate and tiny altcoin networks with very little hashrate and no incentive to increase it either.

For example ethereum network that you are talking about here had never had the incentive to expand beyond  certain level due to its uncertain future, lack of utility, difficulty bomb that has existed from day one and kept being pushed back, threat of changing algorithm,... Basically they prevented the hashrate from growing now there is a big risk of 51% attack. Same with altcoins with low hashrate that also had successful attacks.

[Husires]

An attack of this size will only happen under the supervision of a state you require many mining devices that all need cost + electricity. Which means that you need to burn a lot of money with zero benefit in return.
The success of this attack depends on two factors, which is that the attack continues for the longest possible time and other minners stop mining.

Obtaining 51% will not happen unless there is cooperation with the existing mining pools and most likely they will not respond because they will lose an opportunity that was profitable to them.

[ranochigo]

Government state can print unlimited amount of money. Beside, what if they don't even have to purchase the ASICs? They can just confiscated the mining equipment from miners (very plausible in authoritarian states like Russia or China where government has lots of power).

Unlike what people think, governments cannot print money at will. There are severe repercussions when a government prints money at above normal rates, which actually could result in a failure of the economic systems.

Governments, at least as of now still rakes a significant portion of money through cryptomining by the employment, taxes, ASICs manufacturers, etc. There is just simply no incentives for them to kill of the whole industry; an attack like this happens once. After that, the attack gets exponentially harder to reap any benefits and another Bitcoin with a different algorithm springs out. You have just wasted all your ASICs and your electricity and crypto survives.

In PoS it's actually exponentially more expensive to sustain an attack as the stake of the attacker is destroyed. They would have to keep buying coin from a decreasing supply at an increasing price, which would tend to infinity.

In PoS, you are not exchanging anything. PoW functions on the premise that some form of resources is being used up in exchange for getting a block. If those who holds a greater "stake" are permanently at an advantage, then why wouldn't the network be worse off? What would be the deterrent if the government manages enough resources to seize/purchase enough funds?