The attack is 51%. The Bitcoin killer.

[soulmates]

Every self-respecting crypto enthusiast has heard about the 51% Attack, in which an error can occur in the Bitcoin code and I think you understand how this will end.

And so, the capitalization of Bitcoin at the moment is about $ 700 billion, if the United States in conjunction with other states wants, they will be able to easily attack Bitcoin and stop its existence.

Or do they want to start using this market themselves to extract their own profit and earn money? Maybe they are trying to limit only ordinary citizens, and they have been sitting on the market for a long time?

There are a lot of incomprehensible questions, a topic for reasoning, what do you think?

[franky1]

maybe searching the forum for the thousands of topics on the subject. instead of making yet another one.

its not about fault with bitcoin code. its about a mining pool wanting to undo a block. after they have received goods or service. (undo some transaction) so that they can re-use that transaction value elsewhere

(its a double spend risk. not a break bitcoin code risk. as all network fullnode users have the same moral code. and changing block formations wont change the code. it only changes whats been a confirmed transaction)

the whole idea is
if it costs a block $200k every 10 minutes to be made.
to undo a block
say block 601
the moral mining pool(MMP) and the general network are already working on block 602
immoral pool(ImP) makes a new 601 minus his transactions

            0min   10min   20min   30min   40 min  50 min
MMP      601      602
ImP       601  601

for ImP to overtake MMP, ImP has to have more hashpower then the network.
            0min   10min   20min   30min   40 min  50 min
MMP      601      602      603       604
ImP       601  601  602  603  604

and maintain it
            0min   10min   20min   30min   40 min  50 min
MMP     601      602      603       604
ImP      601  601  602  603  604  605  606

thus at 605 everyone then follows his chain. thus ditching the mmp chain of 601-604
what he doesnt want to do is have the MMP overtaking him and re-establishing the 601 with the transaction
            0min   10min   20min   30min   40 min  50 min
MMP     601      602      603       604
ImP      601  601  602  603  604  605  606

anyway in stepping back to a scenario ImP was not re-overtaken
            0min   10min   20min   30min   40 min  50 min
MMP     601    602      603       604
ImP      601  601  602  603  604  605  606

this scenario now any/all transactions that were on mmp 601-604 are no longer confirmed.
and any transactions on ImP version are confirmed

however this cost ImP in this simple demo $1m of power to overtake with the 605 variant chain block
.
the premiss is.. unless people are going to want to undo a large transaction over $1m, they wont try to do this attack. as its not worth it otherwise

which is why as a more dis-incentive. anyone receiving a transaction will not release goods of $1m for 6 blocks(block cost $1.2m)

meaning if ImP buys something for $1m at block 601 he wont get the goods until 607
and then and only then can he try to break the 601 and start his undo of that transaction

           0min   10min   20min   30min   40 min   50 min   60 min   70 min   80 min
MMP     606      607       608       609      610       611       612       613        614
ImP      601  602  603  604  605  606  607  608  609  610  611  612  613  614  615

now its cost him 14 blocks ~$2.8mill
to undo a transaction of just $1m value

thus. he has lost money.. and would have been better off just being a moral miner

[ranochigo]

This topic has been discussed so rigorously and the conclusion is always that no reasonable state or adversary would spend so much resources on trying to stop something so insignificant. Unless you're looking for any sorts of profits, 51% won't work. You are bound to spend a few billions in both the hardware, facilities, electricity and various other miscellaneous costs for such an insignificant attack. The money could be better used in other areas. You COULD diminish the confidence that people has in Bitcoin but another crypto would simply rise again and the cycle continues. Not to mention that ASICs are not that easy to obtain or operate in bulk.

[soulmates]

This topic has been discussed so rigorously and the conclusion is always that no reasonable state or adversary would spend so much resources on trying to stop something so insignificant. Unless you're looking for any sorts of profits, 51% won't work. You are bound to spend a few billions in both the hardware, facilities, electricity and various other miscellaneous costs for such an insignificant attack. The money could be better used in other areas. You COULD diminish the confidence that people has in Bitcoin but another crypto would simply rise again and the cycle continues. Not to mention that ASICs are not that easy to obtain or operate in bulk.

I don't think that if a 51% attack happens, then the coins in addition to Bitcoin will live, immediately a panic will start in the market and everyone will sell Bitcoin, because no mistakes should occur, and canceling transactions is quite the opposite of what Bitcoin was created for.

Of course, maybe in the future there will be a new coin that will be protected from such manipulations, but it will take at least 5 years to restore trust for people, I think so

[MusaMohamed]

I don't think that if a 51% attack happens, then the coins in addition to Bitcoin will live, immediately a panic will start in the market and everyone will sell Bitcoin, because no mistakes should occur, and canceling transactions is quite the opposite of what Bitcoin was created for.

Of course, maybe in the future there will be a new coin that will be protected from such manipulations, but it will take at least 5 years to restore trust for people, I think so

The Hash Power Migration since China crackdown causes a drop of more than 51% of total hash power from the peak. If any corporations, person can collect all those hash power, it would give that entity enough hash power for 51% attack.

It is impossible to collect all those ASICs into one entity. In the past, there are pools from same owners that had more than 51% hash power but they did not do any attack on the network. Because it will cause harm for Bitcoin and for everyone. It is stupid to run 51% attack.

[ranochigo]

I don't think that if a 51% attack happens, then the coins in addition to Bitcoin will live, immediately a panic will start in the market and everyone will sell Bitcoin, because no mistakes should occur, and canceling transactions is quite the opposite of what Bitcoin was created for.

Of course, maybe in the future there will be a new coin that will be protected from such manipulations, but it will take at least 5 years to restore trust for people, I think so

51% is not unknown and the costs and complexity of executing it is how PoW solves the Byzantine general problem. If you think governments care about Bitcoin at all, to the extent that they're willing to spend billions on trying to harm the current Bitcoin, then you are wrong. You cannot prevent 51% attack but the opportunity costs that arises from this is immense. If it ever happens, then we roll back to before the attack and change the algorithm. By doing so, the government has effectively wasted billions of dollars for nothing.

51% attack is not a Bitcoin killer because the game theory behind it hasn't failed. The sheer energy required to execute the attack is equivalent to certain smaller countries. The land area required to house the ASICs and the manpower required to set it up would be fairly big as well. Without understanding the difficulty of executing an attack, and the benefits of doing so from the government's PoW, then you won't understand why this isn't a problem.

[20kevin20]

Bitcoin can't be "stopped from its existence" through a 51% attack. Worst it can do is just temporarily make things confusing, but in the end the Bitcoin code is editable which makes it easy to counterattack. As mentioned earlier, if Bitcoin fails, another coin will rise anyway and so their attempt to destroy cryptocurrencies would be worthless.

Bitcoin can be attacked, but the counterattack may be even worse for the enemies. It's like shooting a soldier who keeps coming back alive, making you literally waste bullets in the end.

[joniboini]

Of course, maybe in the future there will be a new coin that will be protected from such manipulations, but it will take at least 5 years to restore trust for people, I think so

Well, before we talk about restoring trust, we should discuss whether it's possible to lose it in the first place. If there is a chance that an attack will happen, I'm pretty sure the community will prepare for the countermeasures. Your panic sell situation has been described and predicted multiple times but Bitcoin is still doing fine. Sure, everyone knows 51% is deadly, but it's not like anyone can pull the trigger and kill the network anytime.

[Robinson66]

If every country opposes Bitcoin and attacks Bitcoin, it may reach 51%, but there is no reason for every country to unite to attack Bitcoin and not merge, because it requires strong financial and computing power. They will only oppose Bitcoin or ban Bitcoin (but no country can completely ban the possession and use of Bitcoin), and they may ban mining or trading. . Individuals cannot attack the total computing power to 51%. So they cannot successfully attack Bitcoin.

[Jating]

Every self-respecting crypto enthusiast has heard about the 51% Attack, in which an error can occur in the Bitcoin code and I think you understand how this will end.

Wrong, it's not about error in bitcoin code, Lol, it's about some entity controlling 51% of bitcoin's hashrate.

And so, the capitalization of Bitcoin at the moment is about $ 700 billion, if the United States in conjunction with other states wants, they will be able to easily attack Bitcoin and stop its existence.

Yes, that is feasible, but what do they get in return? Nothing, there are no incentives and on the contrary, it might cause billions to attack bitcoin.

Or do they want to start using this market themselves to extract their own profit and earn money? Maybe they are trying to limit only ordinary citizens, and they have been sitting on the market for a long time?

There are a lot of incomprehensible questions, a topic for reasoning, what do you think?

Again, there will be no profits in 51% attack, they are just going to waste a lot of their time and money out of nothing. It is not logical.

[Kakmakr]

The real threat come in when 51% of people in this world do not understand what a "51% attack" is and they post misinformation like this on a public forum. Luckily for us, more than 51% of the people in the Bitcoin community know what it is and some of us even experienced a close call, when the GHash.io mining Pool nearly acquired 51% of the hashing power.

We also know shills love to talk about "51% Attack" as if it is a huge threat to Bitcoin, but we just smile at those posts and we go on with our lives, because we know the facts.     (Done that.... got the T-Shirt.... )  

Facts : To sustain a 51% Attack is VERY expensive and definitely not profitable and if governments target 1 Crypto with that, then we just shift to the next Crypto and laugh all the way to the Bank.    (Tax money can only be wasted for a while, before the tax payer and voter starts to riot and not vote for that government)

[Obito]

51% attack doesn't benefit anyone, even if the states who will support, collaborate and execute the attack won't get anything but just satisfaction that they did something plus bitcoin can recover from it even if in theory, it's a devastating attack. Also, with China out of the picture, it will be difficult to coerce every miner to participate in this one because not everyone will yield unless you use force which is going to be making noise and you don't want noise since people get nosy when there's noise.

[soulmates]

I don't think that if a 51% attack happens, then the coins in addition to Bitcoin will live, immediately a panic will start in the market and everyone will sell Bitcoin, because no mistakes should occur, and canceling transactions is quite the opposite of what Bitcoin was created for.

Of course, maybe in the future there will be a new coin that will be protected from such manipulations, but it will take at least 5 years to restore trust for people, I think so

The Hash Power Migration since China crackdown causes a drop of more than 51% of total hash power from the peak. If any corporations, person can collect all those hash power, it would give that entity enough hash power for 51% attack.

It is impossible to collect all those ASICs into one entity. In the past, there are pools from same owners that had more than 51% hash power but they did not do any attack on the network. Because it will cause harm for Bitcoin and for everyone. It is stupid to run 51% attack.

That is, simply storing 51% of the total amount of Bitcoins on the wallet will not help to make an attack? Do you need exactly 51% of the capacity of bitcoin, computing machines that ensure the operation and security of the network?

The real threat come in when 51% of people in this world do not understand what a "51% attack" is and they post misinformation like this on a public forum. Luckily for us, more than 51% of the people in the Bitcoin community know what it is and some of us even experienced a close call, when the GHash.io mining Pool nearly acquired 51% of the hashing power.

We also know shills love to talk about "51% Attack" as if it is a huge threat to Bitcoin, but we just smile at those posts and we go on with our lives, because we know the facts.     (Done that.... got the T-Shirt.... )  

Facts : To sustain a 51% Attack is VERY expensive and definitely not profitable and if governments target 1 Crypto with that, then we just shift to the next Crypto and laugh all the way to the Bank.    (Tax money can only be wasted for a while, before the tax payer and voter starts to riot and not vote for that government)

The capitalization of Bitcoin is more than 40% of all funds on the market and why do you think that if an attack is made and Bitcoin dies, then other coins will live?

Everyone knows what impact Bitcoin has on the prices of other cryptocurrencies.

[o_e_l_e_o]

That is, simply storing 51% of the total amount of Bitcoins on the wallet will not help to make an attack?

The number of coins you own is irrelevant to a 51% attack. You can attack the network despite not owning any bitcoin.

Do you need exactly 51% of the capacity of bitcoin, computing machines that ensure the operation and security of the network?

No. You need a sustained minimum of 51% of the total hashrate to guarantee that your attack will be successful over a long enough time frame. You can have much more than this, but you could also try to attack the network with much less than this, although your chances of success exponentially decrease.

The capitalization of Bitcoin is more than 40% of all funds on the market and why do you think that if an attack is made and Bitcoin dies, then other coins will live?

There are maybe two or three which I could see surviving, albeit after taking an enormous hit to their price. But if bitcoin dies, then the majority of the market dies with it.

[dzonikg28]

This topic has been discussed so rigorously and the conclusion is always that no reasonable state or adversary would spend so much resources on trying to stop something so insignificant. Unless you're looking for any sorts of profits, 51% won't work. You are bound to spend a few billions in both the hardware, facilities, electricity and various other miscellaneous costs for such an insignificant attack. The money could be better used in other areas. You COULD diminish the confidence that people has in Bitcoin but another crypto would simply rise again and the cycle continues. Not to mention that ASICs are not that easy to obtain or operate in bulk.

What would also kick in is what I just call the "Hydra-phenomenon" for now. If you attack Bitcoin and succeed in rewriting a block or two and thereby harm the network or even destroy it, that is not going to be the end of decentralized currencies. So even a state with malicious intent and the will to lose billions of dollars is aware of the fact that firstly, there are already a ton of other networks that must be attacked as well and secondly, if the first attack on Bitcoin is enough to also tear down all other cryptos, a new protocol with security adjustments will definitely appear shortly after. I think Bitcoin is just a genius invention particularly because it is open source and you could tweak all kinds of aspects about it to get it going again even in another version.

[dkbit98]

Every self-respecting crypto enthusiast has heard about the 51% Attack, in which an error can occur in the Bitcoin code and I think you understand how this will end.

51% attack is NOT some error in Bitcoin code and I don't know how you got that idea in the first place 
Taking over mining hashrate for Bitcoin is almost impossible task, some people tried to take over with various forks but they failed, this is most secured computer network in the whole world, and anyone willing to throw away many can try that again and se how it goes.

[MusaMohamed]

That is, simply storing 51% of the total amount of Bitcoins on the wallet will not help to make an attack? Do you need exactly 51% of the capacity of bitcoin, computing machines that ensure the operation and security of the network?

Miners need to own 51% of hash power on the network and maintain it for a while in order to do 51% attack. It is very costly if you have to hire hash power from any source and many full nodes will detect suspicious things. They will switch to other pools and the community will have solutions to stop the attack.

You are wrong because hash power is needed to run attack. Not Bitcoin. Miners need of have ASICs, and they don't need to have Bitcoin to confirm Bitcoin transactions. Same, they don't need to have Bitcoin to do 51% attack on Bitcoin network.

[aoluain]

-snip-

thus. he has lost money.. and would have been better off just being a moral miner

Exactly, if anyone or group of people had the hashpower/computing power to
attack the network it would be far more rewarding to actually help the network
and mine to earn a Bitcoin reward.

As franky1 mentioned this topic has been discussed many many times on the forum.
The question has been asked since 2011

https://bitcointalk.org/index.php?topic=52388.20
https://bitcointalk.org/index.php?topic=44078.0
https://bitcointalk.org/index.php?topic=55394.0

[nelson4lov]

This topic has been discussed so rigorously and the conclusion is always that no reasonable state or adversary would spend so much resources on trying to stop something so insignificant. Unless you're looking for any sorts of profits, 51% won't work. You are bound to spend a few billions in both the hardware, facilities, electricity and various other miscellaneous costs for such an insignificant attack. The money could be better used in other areas. You COULD diminish the confidence that people has in Bitcoin but another crypto would simply rise again and the cycle continues. Not to mention that ASICs are not that easy to obtain or operate in bulk.

Yeah, it would be really pointless to even make an attempt at such a venture. 51% attack topics used to be a thing in the early days of the forum but stopped being one as more and more people got into crypto. I don't see why any organization or country would want to do something like that. Considering how much it would cost to execute such an attack. So much efforts for very little reward.

[soulmates]

That is, simply storing 51% of the total amount of Bitcoins on the wallet will not help to make an attack? Do you need exactly 51% of the capacity of bitcoin, computing machines that ensure the operation and security of the network?

Miners need to own 51% of hash power on the network and maintain it for a while in order to do 51% attack. It is very costly if you have to hire hash power from any source and many full nodes will detect suspicious things. They will switch to other pools and the community will have solutions to stop the attack.

You are wrong because hash power is needed to run attack. Not Bitcoin. Miners need of have ASICs, and they don't need to have Bitcoin to confirm Bitcoin transactions. Same, they don't need to have Bitcoin to do 51% attack on Bitcoin network.

How exactly will the capacity be transferred to other pools? Do they automatically do it or am I misunderstanding something?

The system is completely transparent and decentralized.

[NeuroticFish]

or am I misunderstanding something?

I suggest you read how mining and pool mining happens, maybe also what it does. (info)
Then I suggest you read a little about 51% attacks and double spending. (more info)

And only afterwards you are good to go with this kind of topics.
It's OK that you don't know everything. Just you "jumped in" and missed the start.


Edit: I've added two links as info. I'm not affiliated with that website but at a first glance it looks pretty informative.

[BrianH]

I don't think that if a 51% attack happens, then the coins in addition to Bitcoin will live, immediately a panic will start in the market and everyone will sell Bitcoin, because no mistakes should occur, and canceling transactions is quite the opposite of what Bitcoin was created for.

Of course, maybe in the future there will be a new coin that will be protected from such manipulations, but it will take at least 5 years to restore trust for people, I think so

If you think governments care about Bitcoin at all, to the extent that they're willing to spend billions on trying to harm the current Bitcoin, then you are wrong. You cannot prevent 51% attack but the opportunity costs that arises from this is immense. If it ever happens, then we roll back to before the attack and change the algorithm. By doing so, the government has effectively wasted billions of dollars for nothing.

51% attack is not a Bitcoin killer because the game theory behind it hasn't failed. The sheer energy required to execute the attack is equivalent to certain smaller countries. The land area required to house the ASICs and the manpower required to set it up would be fairly big as well. Without understanding the difficulty of executing an attack, and the benefits of doing so from the government's PoW, then you won't understand why this isn't a problem.

Agree with some of what you said, but governments absolutely do care about Bitcoin. When you have major enterprises like VISA, Amazon, Twitter, banks, etc. starting to use it and it poses a threat to the central banks fiat currency control, they are starting to take notice. That's why you hear all this noise about stablecoins, because governments see this as a way to destabilize crypto and a direct threat to CBDC - they're missing out.

A few billion to destabilize Bitcoin would absolutely happen, if governments thought it would work. While you couldn't practically change the algorithm, people would switch to a different crypto before it happened, making the effort pointless. Bitcoin is one serpent head among the medusa's head of snakes. They can try to cut off one head, but PoS or something else would just take over.

If every major country banned/bought out cryptos, they could theoretically discourage it, but I think they see the futility in that and are going to try to tax and regulate it somehow. CBDC is one way to do this. CBDCs maintain the surveillance and allow them to monitor users onramp/offramps into the system. Some say Bitcoin was developed by governments so they could even better track us than the private/public banking system we have now.

Too many elites making money off of it and manipulating the masses into buying/selling through influencers like Musk/Bezos/Dorsey pushing the herd of sheeple in the direction they want them to go, just like they do with stocks.

[OgNasty]

I don't think a successful 51% attack would kill Bitcoin at this point nor do I think anyone capable would be willing to attempt it.  It would take a great deal of equipment and money to pull off such a thing.  I do like the idea of governments with massive amounts of hashrate closely monitoring chains for any sort of forking while they wait for a massive transaction to receive confirmations.  Makes me think of the new Loki show and divergent timelines being managed by the timekeepers...

[dzonikg28]

I don't think a successful 51% attack would kill Bitcoin at this point nor do I think anyone capable would be willing to attempt it.  It would take a great deal of equipment and money to pull off such a thing.  I do like the idea of governments with massive amounts of hashrate closely monitoring chains for any sort of forking while they wait for a massive transaction to receive confirmations.  Makes me think of the new Loki show and divergent timelines being managed by the timekeepers...

And if a government tried to attack Bitcoin, wouldn't it be extremely likely that they will be exposed? How could you pull off such a massive operation, whether it be hardware orders or electricity going through the roof at a specific geolocation, or anyone else involved in the operation saying a single word, the government/actor trying it would almost certainly be exposed.

Is there any way to roughly identify the geolocation of the hashrate production through means other than whistleblowing or obvious behavior like huge hardware orders?

[hd49728]

And if a government tried to attack Bitcoin, wouldn't it be extremely likely that they will be exposed? How could you pull off such a massive operation, whether it be hardware orders or electricity going through the roof at a specific geolocation, or anyone else involved in the operation saying a single word, the government/actor trying it would almost certainly be exposed.

They can succeed but in a short period only. The Bitcoin community will detect their attacks and react quickly to stop governmental attacks.

Is there any way to roughly identify the geolocation of the hashrate production through means other than whistleblowing or obvious behavior like huge hardware orders?

Geolocations don't mean they are identities of ownership. In same geolocations, you can find different mining companies and their hash rates belong to different owners.

Full nodes can detect IP address as I know. I read some documents that in order to have better privacy for your bitcoin transactions, you should set up your Bitcoin full nodes and broadcast your transactions from your full nodes.

[NeuroticFish]

I don't think a successful 51% attack would kill Bitcoin at this point nor do I think anyone capable would be willing to attempt it.

While - at least on paper - 51% is not impossible, if that would happen it would be a blow for Bitcoin's credibility and the way of handling it could keep it alive ... or not (i.e. indirectly killing it). But it's a way too hypothetical situation and imho OP's question/problem was caused by lack of knowledge (and hopefully that was handled too).

[o_e_l_e_o]

if that would happen it would be a blow for Bitcoin's credibility and the way of handling it could keep it alive ... or not (i.e. indirectly killing it).

I agree with OgNasty in that I think bitcoin would probably survive a short and specific 51% attack. By that I mean a 51% attack which double spends a handful of specific transactions, as opposed to a prolonged and sustained attack just mining empty blocks to censor the entire network, or something similar.

There are too many people involved in bitcoin who either don't care or don't understand the importance of a 51% attack, blocks being orphaned, or transactions being reversed or censored. Look at some of the "top" altcoins. Ethereum - not a classic 51% attack but effectively the same result (majority of hash rate reversed some transactions), creating Ethereum Classic in the process, which itself has been 51% attacked several times. XRP, USDT, BNB - completely centralized, can have transactions reversed or censored at any time by their owners. BCash - successfully 51% attacked. And yet all these coins continue to have volumes of billions of dollars and attract new users.

Provided that the 51% attack was short lived, and bitcoin continued to function normally afterwards, then there might be a hit to the price, but I don't think it would be the end of bitcoin.

[NeuroticFish]

By that I mean a 51% attack which double spends a handful of specific transactions, as opposed to a prolonged and sustained attack just mining empty blocks to censor the entire network, or something similar.

That's what I also meant, although indeed a state could do huge damage if it would manage to pull a sustained attack like you mentioned.

And yet all these coins continue to have volumes of billions of dollars and attract new users.

Ethereum had quite a blow back then. And the rest of the coins you've mentioned are imho speculation coins, so the comparison with Bitcoin may not be correct/good.

Provided that the 51% attack was short lived, and bitcoin continued to function normally afterwards, then there might be a hit to the price, but I don't think it would be the end of bitcoin.

I hope you're right. Or, even better, I hope that we'll never find out.

[BlackHatCoiner]

Suffice it to understand what you're attacking. The revolution set sail; you can't stop it, just like you can't kill an idea.

Seriously, think it. Do you really believe that after this revolutionary creation, people will simply forget it? That this innovative technology will be gone just because the government says so? That we'll let slip the PoW mechanism combined with a chain of blocks containing immutably information?

By attacking Bitcoin, you actually attack your own wealth. Masochism...

There are maybe two or three which I could see surviving, albeit after taking an enormous hit to their price. But if bitcoin dies, then the majority of the market dies with it.

Which ones do you have in mind?

Ethereum - not a classic 51% attack but effectively the same result (majority of hash rate reversed some transactions), creating Ethereum Classic in the process

Isn't Ethereum fine? I've read that ETC was 51%-ly attacked, but that was long after ETH was hard forked. Ethereum Classic was made due to a hack of a third party project.

[o_e_l_e_o]

Do you really believe that after this revolutionary creation, people will simply forget it? That this innovative technology will be gone just because the government says so? That we'll let slip the PoW mechanism combined with a chain of blocks containing immutably information?

As much as I think almost all altcoins are either trash or scams, bitcoin is not the only possible incarnation of a decentralized peer to peer currency. The idea might never die, but that does not mean that bitcoin is invulnerable to attack.

By attacking Bitcoin, you actually attack your own wealth. Masochism...

There is no requirement to own bitcoin to attack it. A government which sees it as a threat to their fiat monetary system could be attempting to preserve their wealth by attacking bitcoin.

Which ones do you have in mind?

No idea. I don't really follow altcoins very much. The only altcoin I hold is Monero, for obvious reasons given my feelings regarding privacy.

Ethereum Classic was made due to a hack of a third party project.

Ethereum Classic was made because a majority of Ethereum developers decided they wanted to reverse some transactions which had taken place on the Ethereum network, not unlike a 51% attack. Those who decided that developers shouldn't be allowed to reverse transactions they don't like forked the network to create Ethereum Classic.

[BlackHatCoiner]

As much as I think almost all altcoins are either trash or scams, bitcoin is not the only possible incarnation of a decentralized peer to peer currency. The idea might never die, but that does not mean that bitcoin is invulnerable to attack.

But, Bitcoin, after all, is an idea. The fact that someone may catch up and gain the majority of the votes doesn't mean that he ruins the system. It's an idea which transforms human's greed to common good, which discourages you from attacking it, but rather helping it so you can earn the most.

There's harmony in this consensus and the only ones who can destroy it are the ones who make this beautiful melody.

There is no requirement to own bitcoin to attack it. A government which sees it as a threat to their fiat monetary system could be attempting to preserve their wealth by attacking bitcoin.

You may need no Bitcoins, but you need wealth. You can't plan to spend billions of dollars worth of ASICs and electricity and retain their work until further notice (?), without damaging your own wealth. Besides, what could they do on a PoS crypto? Buy half of its units? They can't attack everything and that makes the 51% attack of Bitcoin meaningless.

No idea. I don't really follow altcoins very much. The only altcoin I hold is Monero, for obvious reasons given my feelings regarding privacy.

There are greater achievements in terms of technology than Bitcoin. Sure thing, it was created in 2009 which has its downsides. Phenomenonically, it'll always be the #1, but in terms of privacy (e.g.), it can't be compared with Monero (e.g. again).

In my opinion, without Bitcoin the whole industry would become chaotic.

[o_e_l_e_o]

The fact that someone may catch up and gain the majority of the votes doesn't mean that he ruins the system.

If by "votes" we are talking about hash power, then that's exactly what it means. If someone consistently controls 51% of the hash power, they become a centralized third party which can censor any and all transactions they do not like. At that point bitcoin is no longer trustless, decentralized, or censorship resistant. That's incredibly unlikely, yes, but never impossible.

The idea of bitcoin might survive such an attack, but bitcoin itself would only survive with a hard fork to brick the attacker's (and everyone else's) ASICs, or something similar.

[stompix]

You may need no Bitcoins, but you need wealth. You can't plan to spend billions of dollars worth of ASICs and electricity and retain their work until further notice (?), without damaging your own wealth. Besides, what could they do on a PoS crypto? Buy half of its units? They can't attack everything and that makes the 51% attack of Bitcoin meaningless.

People sometimes overestimate the cost for this, they take new gear at resale value, they think in power at residential tariffs and so on..

To launch a 51% you would need roughly 1 million s19pro, that would be 7-8 billion $.
But if I would do that I wouldn't go for that gear, I would grab s9s that sell for around 250$, and instead of paying 8k for 110th/s I would get away with 1500$.  So rather than 8 billion, you're down to 1 and a half. And there is a ton of cheap useless for ROI gear sitting in China with no buyer, you're not going to make a profit with it but you'll definitely get a far better price per TH than with the newest generation. Besides, you don't need it to run for a year, one week and it's enough.

The other thing is energy, the first part is quite amusing, every time when it's about bitcoin, everyone says bitcoin is using only 0.01% of the energy in the world, now when you need to attack it, god that's a lot of energy and nobody can get it!!!! Back to the math, miners can't spend more on energy than the reward, so to match them you will need to spend a max of 45 million a day, but you're the government so no taxes, it will get way cheaper. If we go by 10cents/kwh it will still only cost 20 millions to power 6 million s9 a day.

Now, let's assume that indeed Bitcoin is threatening the US dollar, and the US who spends 13 billion on a Ford-class carrier won't be able to pull that off?
But nobody is interested to do so, why do it?  It means people in your own country losing wealth, it means stopping an activity and dealing with people that once had a job and now are on the unemployment payroll, why? Because it will replace the dollar and it will do that and that? Common...

Seriously, think it. Do you really believe that after this revolutionary creation, people will simply forget it? That this innovative technology will be gone just because the government says so?

Once the value is gone so is the hype. The idea for which Bitcoin was created get's more tainted every day, look at the ecosystem now, it's all about centralized exchanges and wallets, prices and trading, and holding till you make x in profit, once that is gone you will never be able to find the same userbase again, the ones that are reticent to the idea will never embrace it after such a failure, and from their point of view is quite understandable.

[ropyu1978]

it's true that 51% of bitcoin killers attack, want to destroy and bring down bitcoin, but all of their attacks to destroy bitcoin, it can be said to be unsuccessful, they failed miserably, haters have always instigated bitcoin, everything they do, but bitcoin has a way separately to overcome all the attacks that come..

[BlackHatCoiner]

Now, let's assume that indeed Bitcoin is threatening the US dollar, and the US who spends 13 billion on a Ford-class carrier won't be able to pull that off?

I'm just saying that there's no reason to do it. Spend more than a billion dollars to attack something that works under a general agreement. You may indeed achieve to destroy the Bitcoin network, but you won't get rid of your worries. Proof of stake cryptocurrencies will then arise. What will they then do? Buy half of the units? There will be other permissionless and borderless cryptocurrencies they'll be afraid of; beating Bitcoin doesn't beat this liberated attitude.

Once the value is gone so is the hype. The idea for which Bitcoin was created get's more tainted every day, look at the ecosystem now, it's all about centralized exchanges and wallets, prices and trading, and holding till you make x in profit

Yes, this is how the world works, I know. The majority of the people don't want to be responsible for their wealth. Hence, centralization occurs.