Bitcoin Forum

I would like to talk in this thread about the 51% attack and correct me if I'm wrong below.

So let's assume that I have the 51% control of the network. I made a transaction that has been confirmed only 1 time and the last block is 1000.
My transaction will be inside the 999th block. What exactly I have to do in order to reverse that transaction? Rebuild the blockchain? Or building again the 999th block, then again the 1000th block and then I'll have to be the first that mines the 1001st block?

But even if it's too expensive and too unprofitable it's still possible. And I know that none of us would want that, because of the loss of fortunes (bitcoin price would drop). Some goverments tho, would want to destroy the bitcoin network and of course they can easily afford it.

Thoughts? Do you believe that goverments can control it? And please correct me if I'm wrong about the 51% attack, because I haven't fully understood it.

If you are willing to spend $24 millions per day with the additional cost of ASIC you can try to destroy the network, then what happens, what is the final outcome by spending billions to destroy a network and a government cannot spent tax payers money to carry on an attack on a financial sector.

It was possible for a government or anyone when Satoshi released the first software back in 2009 and in the initial years even Satoshi did not want unwanted exposure until everything is tested and bugs are identified.

So the answer is no, no government will spent billions nor millions to destroy the BTCitcoin network.

If you want to know about the 51% attack in different crypto network, here is a site crypto51 (https://www.crypto51.app/coins/BTC.html)

It has to be an expensive attack so if officials in the government can see the benefit of doing it and are willing to spend that much, we don't know if they can afford to spend that much.
There's more other things that they can point focus to spend that amount with their projects than use it with an attack to bitcoin's network.

They can try! But we had a chance to experience very recently (actually a few months ago) what communities might have happened when they opposed authority. When Justin tried to take Sun Steem under his auspices, the community uncovered HIVE. So, as you said, they can try to do something using state power. But the community will always have an answer!

Yes. They have a plan.

Keep the Bitcoin block size at 1 MB and move the bulk of transactions to LN node operators who instead of cryptographically proving transactions are exposed to regulatory KYC/AML oversight as custodians and transmitters of user's funds.

I was watching one of your threads recently. Well... I don't understand you very much. What's KYC/AML and who will move the bulk of TX to LN node operators?

imagine the current block was 630,000
and you had a transaction in block 629,000

to go back and edit the transaction(remove the transaction from block 629,000) you then have to rebuild every block afterwards

with 51% it would take a week to catch up to to 630k (1k blocks at ~10min each)
but whilst your wasting that week. the rest of the network was always moving ahead and is now on 631k
meaning your always a step behind.

you would need substantially more then 51% to catch up and overtake the main network and even if you could catch up and overtake. there is no guarantee that your chain would win and orphan off the chain history of 629-630k+ of the main network

miners 51% cannot change the rules. all that can possibly be at risk is 'empty blocks'/double spend (basically changing previous / deciding future transactions are in a block)

my personal node has a warning if there was a chain rearrangement of more than 6 confirms(blocks) and other smart devs probably have similar mechanisms to monitor the blockchain. mine and others have other monitoring checks like how many empty blocks appear. and other things that are not just the normal 'checklist'

@franky1, I didn't mean to go back a thousand blocks. Yeah that's almost impossible. Just to previous block, change one transaction and then start mining the new block.

true network:  1 2 3 4 5 6 7 8 9 10
51% attacker: 1 0 1 2 3 4 5 6 7 8 9 10

attacker is 2 blocks behind.
remember the attacker does not earn the block rewards of his chain unless he can get the general network to accept his chain. which means more then just catching up and overtaking.
so alot of money upfront needs to be paid out to perform it. without guarantee's of returns

so trying to double spend a $2 coffee is not worth it if its gonna cost millions of dollar just to get 51%
to solve each block costs over $80k
at 51% you will never catch up

also if you took the hashrate of 120 exa
just to match the hashrate to have a 51% .. would need 1.7million asics of ~70t/hash
at over $1k a asic would cost over $1.7billion in equipment

https://learnmeabitcoin.com/guide/images/51-attack/51-attack.png


So I see it like this:
true network: 1, 2, 3, 4, 5
attacker: 0, 1, 2, 3, 4, 5, 6

Correct me please. I want to understand this kind of attack but it seems to be more complicated that I thought...

Some altcoins had 51% attack (in the form of reversing transaction) successfully executed against them and they barely dropped in price. Of course if it happened with Bitcoin it would cause some panic, but Bitcoin is built on strong game theory fundamentals - you need to keep spending money to attack it, so even if such attack happened, users would understand that it cannot last long, and their confidence won't be shattered.

You also need to understand that 51% doesn't give you some sort of total control over the network, it just gives you a control over which valid transactions to include in next blocks.

That is where you are wrong.
 People can destroy government anytime they want .
Government needs to understand that they are not the ruler , they are the caretaker of their nation and it is a Preety big thing to actually be able to help everyone with .
Bitcoins and cryptocurrencies are again a remark for everyone that the power is in the hands of everyone and one should always take it as a responsibility.
Even without any middle man or centralized body one can function properly.

'to replace transactions already mined'
so if you had a cup of coffee tx in current block (1). and wanted to edit it you have do 1 twice which would be 1,1,2.. (you already had 1 then edited it before moving forward)
but if the current block is 1 and you wanted to edit PREVIOUS block(0)
you got to edit 0, then make new 1 which is 1 0 1 2 3

---

so you know your not gonna get returns from your CSW investments. but hoping to profit from selling books pretending you went to a farm and dry humped a guy that told you a fake name..
sounds like the title should be 'confessions of a grindr user'

[moderator's note: consecutive posts merged]

^ Surely the government can but will they spend millions of dollars just to destroy a network where there are tons of programs and projects that they need to focus more and spend the funds especially this time of crisis. Probably if the government will destroy bitcoin and cryptocurrency it has no direct benefit for them it will just be a waste of time and funds for them. But still, the crypto world should not be lenient because there may be time for the government will really try to attack the crypto world because they don't benefit as well on us.

Why complicate with a 51% attack or something similar? If there were a consensus at the level of the world's most powerful governments, the vector of attack could simply be directed over what governments have as their strongest weapons - laws. If Bitcoin were to be declared illegal, all existing infrastructure would be shut down, and without crypto exchanges and bans BTC as a means of payment, things would seem rather pointless.

Such a scenario, of course, is not destruction - but the relocation of Bitcoin to the underground, where it would be quite inaccessible to most ordinary Internet users.

Bitcoin is  decentralized digital currency which are being used in online. And we all know that this digital currency coins doesn't have any people, person and company behinds it. It just always depends on its availability and stocks. One of the situation that may happen in the future is that the government has the power to control thr regulations of the said coin. I guess some of government agencies wanted to claim or to rule over the bitcoin and they always find a way ro manipulate it and to affect the price or product.

I think government can't destroy the bitcoin whatever they want and do. For how many years, bitcoin suprassed its value and meaning all over the world. Bitcoin became one of the largest and strongest coin in digital currency. Thou, it doesn't any people behind it still it makes itself one of the most improved coin in digital. Government will cannot do anything unless they will attack the directlt the person who are using it in order for it to affected.

Now we are making some progress. It's called the Lightning Network.

https://pricecoin.net/bitcoin/will-lightning-network-node-operators-need-a-money-transmitter-license/

It's still partial destruction as everyone'd get out of BTC the moment they say declare it illegal so price would crash. Altcoins would be in an even worse position and would crash to 0 way more brutally. At that point, I'd be in no interest to spend my 10BTC I've bought for $100k and - worst of all - I wouldn't even have where to spend it at anymore as it'd be considered illegal, right?

It's like declaring drugs legal in The Netherlands. It'd cripple the markets in a minute and only few would continue using it illegally, "underground" as you say. But overall, legally, the drug market would be over.

Logically, I'd say this move on the long term would make the "underground" price of BTC skyrocket while the legal markets would value it at $0 - as it'd be banned. I looked up a while ago whether drugs/weapons cost more on the black markets than on the legit ones to make sure I'm correct but found nothing.

Only miners with the 51% network mining power automatically have the potential to block and reverse transaction that already take placr but cant rebuild the blockchain.

The government already have a lot of situation that needed money rather than wasting billions of dollars in 51% attack on bitcoin. The cost to have the 51% mining power is more than you think and if it that simple they would have end bitcoin instead of causing panic then before the KYC/AML was implemented.

This makes sense. Secretly co-opting the network (rather than directly attacking) was much more cost efficient. And effective.

Thank God, or whoever higher power you believe in, that there is no world government.

The power of your government is very limited and if it destroys Bitcoin in your country, you can always move somewhere else. By destroy I mean limit access by blocking the Internet and outlaw it.

If you're afraid that a government will waste money on 51% attacks you should find something better to do. Have you got a hobby?

Don't worry about the things you cannot control. Of course a government can attack the Bitcoin network, but it can also take all your property which is by law called a seizure. Now that you know it's possible, will you be able to sleep at night? ;)

In theory it sounds a bit easier than it really may be. None government would spend billions on organizing 51% attack, they can just ban Bitcoin in their own country.

A well decentralized and secure Bitcoin will be very hard to destroy by normal humans.
By the way,  destroying the assets and transactions of innocent people for being on a good and safer system is immoral and definitely not legal in any just society. I wonder what "government" would do that.

Any digital coin must be accepted by economic entities. This is a lot of small and large companies. For a company to accept a coin, banks must accept it. For banks to accept a coin, the state must accept it, or at least not prohibit it.
The most optimal way to control digital money today is their control by banks. And today it is visible to everyone very well.

Well said, it is quite possible that government could control the crypto currency and the can do whatever they want on it but it would cost a lot of money for them so I don't that they will do it because there are something more productive spending the government money compared of controlling the cryptocurrency, they have more projects to prioritize first before that, they should spend the money regarding to the needs of their people.
Well said, they wouldn't mind first owning the crypto world because they have something to do first before that, they should Open some projects first like government schools, bridges, highways, etc.

They can make their own if they want to and force the citizens to have it. But, I doubt it that citizens who are already into bitcoin will start thinking about what they will implement just to try to get the attention that the people are giving to bitcoin.
They are also intelligent and they are aware that it will be worth a lot of money because if it's not, they have already done it a few years ago or even in our time.

if there's no opposition coming from the public who use bitcoins and cryptocurrency for sure the government can destroy it, but if all people will oppose and explain what is the benefits of blockchain technology together with cryptocurrency for sure the government will think about it. Remember unity can also destroys those drafted plans if the people will unite to defend on what is good to them.

Well, the vast majority of people still unquestioningly obey the laws, whatever they may be, so if Bitcoin were to be declared illegal, there is no doubt that it would be disastrous for the entire crypto system. That's why I say that it doesn't make much sense to discuss the possibility of someone going with a 51% attack, when there are much cheaper measures to make a much bigger effect for much less money.

In the months of the Libra debate, I remember a statement from a US congressman (Brad Sherman) who said Bitcoin was actually still a small baby, and that means it poses almost no threat to the U.S. dollar or any other currency in the world. Compared to the stock, real estate, gold or fiat money markets Bitcoin is really just a small baby that is subject to any manipulation and control.

I know that sometimes it looks like the government is trying to suppress this or that or go against a certain group of people or a certain trend, but most politicians care only about their public image. Banning Bitcoin would show them as puppets to bankers or as people who are afraid of outflow of capital from their country. In other words, it would make them look weak. It's better to tax the shit out of Bitcoin than ban it, as it will automatically scare some people away from it and bring some money to the treasury.

if indeed the government wants to do it then they will do it from the past, now they might also realize the presence of bitcoin can benefit people and the economy of each country, some people also use bitcoin as a commodity or asset to avoid inflation, I am sure there are also individuals from the government who save bitcoin.

I will repeat what I saw in a Bitcointalk ad slot somewhere, even if a government performs a 51% attack they can only alter the transactions they perform, they have no control over other users' transactions.

That is all true but most of governments do not want to supress Bitcoin, no matter that some think. To my opinion this whole story with Bitcoin and governments is exaggerated. It's not in their best interest to destroy Bitcoin but they don't want to allow cryptocurrencies to enher the financial and economy system so easy and without proper regulation.
Yes, there were some examples in some countries where governments wanted to ban the Bitcoin but that were countries they supress human rights and freedom anyway.

No, because you focusing only on technical side. Yes they have money to buy a lot of hardware, yes in theory they can manipulate by that but there is one thing you forgot.
People.
People running Bitcoin, combined in 3 power groups, devs, miners, users (bitcoin servers). If people will realize something fishy happening, they will combine force to get rid of the problem right away. Many ways to counter this :)

That is a fact, the government can destroy and control the crypto world but I don't think that it could happen because they will need to spend a lot of money before they destroy it and I think they would not prioritize first destroying the crypto because they to do some other things more productive than destroying bitcoin. They have to spend money on doing some government projects or they may also need to save it for future sake.
I don't think so, why they would tend to lessen the user of the bitcoin by just making it inaccessible to the most ordinary internet users if they can do it as a whole?

still interesting if they decide they can  afford it how much times it would take

But it doesn't change anything to the current status of Bitcoin and regulatory oversight on centralized exchanges, Bitcoin's base layer is still there.

Plus it's simply NOT TRUE, how are Lightning nodes exposed to regulatory oversight as custodians, and where is it happening right now? NONE. The Bitcoins are not "in custody," they're payment channels.

As I have already written in previous posts, the reason is in the money - and if we generally agreed that 51% of the attack costs a lot, then only by applying laws that are almost free they are practically throwing Bitcoin into the sphere of illegal activities. Despite the fact that today Bitcoin is mostly legal, in some countries like Japan or Germany fully regulated, this does not mean that it is widely used. Any negative measure would be multiple counterproductive for the further advancement of Bitcoin as a currency, and all these theories about a 51% attack at this point make no sense.

Bitcoin is not a threat to anyone at the moment, and given the current state of the world, there are much bigger threats that will be the focus of attention in the coming years.

in order to destroy bitcoin, governments need to act purposefully and the only way to do this is to shorten Bitcoin by fixing its price at $ 1,000 for a long time.  During this time, many cryptocurrency users may lose interest in bitcoin and this will lead to the collapse of the largest cryptocurrency in the world.  but this scenario will not succeed, because no government will donate such a large amount of money, since this idea has rather illusory goals. In addition, a decentralized cryptocurrency system in any case, thanks to an emergency update, will be able to protect itself, which in any case will be supported by a huge number of miners from around the world.

It's theoretically possible,but it's practically pointless,because of the reasons you mentioned.
Spending taxpayer's hard earned money just to destroy the BTC blockchain?Governments aren't that stupid.
Is there a crypto whale(or a group of crypto whales),who will invest billions of dollars just to perform 51% attack and destroy the value of Bitcoin without any clear benefit and without any return of investment?
The governments might hit Bitcoin just by banning cryptocurrency trading and mining,not by a 51% attack.

They will think of it if it's a worth it test. They can do something better with the budget rather than doing the attack. It's not of their priority and the money can be used good in another type of research rather than giving headache to the whole network.
And there's no assurance if they will succeed doing that.

One of the points of Bitcoin is decentralization and the fact that a government or whatever entity CAN'T destroy it. Like literally can't destroy it. The biggest attack a government could do on Bitcoin would be to ban it in the country, which some countries have done. But there's like 200 countries so Bitcoin will continue around the rest of the world wherever it isn't banned. That would simply hurt adoption but not destroy it.

I suppose a government could try a 51% attack, which would actually require them to run 101% of the entire bitcoin network. I mean first off they would have to spend tax payer dollars on attacking the financial industry which would probably be illegal in most countries. Also they wouldn't be able to do that with cloud mining because there aren't enough ASIC miners floating out there in cloud mining services to double the size of the entire bitcoin mining network. So they would have to buy their own miners to double the size of the network, but if they tried to do that ASIC miner inventory would run very low like in 2017 and prices would skyrocket. So it would take a long time and it would cost much more money than you would think based on the current price of miners. And the bitcoin hashrate is increasing quickly most of the time so the longer it took for the government to get their hands on all those miners the harder it would become. Then they'd still need to pay for the many many millions of dollar a day of electricity required to run those miners to attack the network.

But let's say some oppressive gov't (which is needed to be able to legally spend money on attacking a finance sector) does spend all this money over all this time and actually were able to implement the attack. The network could just fork in that event, which I'm sure there would be a consensus about if there was a major concerted attack by a gov't actor to destroy bitcoin, and just like that all that money would have been wasted and Bitcoin would still be going strong.

At this point Bitcoin is by far the most secure network in human history and it would take a truly global scale (not national scale) attack to put it in jeopardy and even then it could be mitigated. Bitcoin was crushable in its early years but not anymore. It's like the end of Terminator 3 when John Conner realizes that skynet isn't running from some central location on hardware that can be destroyed, its just software running on computers all over the world, it can't be destroyed - that's Bitcoin.

The only way to actually "destroy" Bitcoin would be to convince people not to touch it. Which is why that has been the major strategy of people who feel threatened by Bitcoin. It's not a technical attack by a psychological attack. This is why you hear endlessly from certain people in governments or certain people in the financial sector who say its only for criminals and its rat poison or a fraud or a ponzi or whatever absurd lie they tell. And sure it works because you hear plenty of other people parrot what they say. But over time more and more people continue to join Bitcoin so this attack is so far a losing battle for them, but its the only option they have since they aren't smart enough to simply embrace Bitcoin.

Sadly this is what they are doing right now, instead of banning bitcoin they are putting a lot of taxes on it which will force out the people to use it due to extensive taxation. It is true that the government has the ability to manipulate the market in theory, they can just buy a huge amount in the market without us knowing but that would also affect their economy, and just a negation from the tax they have imposed. But from what I am seeing now, from the movement in the market I know anonymous people have already occupied the market and that means they are the ones who's owning it.

Hello everybody. My opinion is that the majority of participants in all the governments of the world strive only for their own gain - this is very simply proved every year by the widening gap between the rich and the poor, Bitcoin is a tidbit to destroy it. As for if these people would like to destroy bitcoin, this is also a very simple answer, and here one does not need to have a better education in the world. Look at the countries that banned Bitcoin, - this is the same as I say early tomorrow morning - the sun, I forbid you to rise, let it always be night. This is nonsense - Bitcoin cannot be prohibited.