Russia could hack the top three mining companies using their existing infrastructure, making the cost of the attack essentially free for them.

Nobody doing this is going to go to Newegg and buy a zillion dollars in new servers. That's not how this would work.

And again, this is the concept that so many people cannot grasp: there are no human beings governing Bitcoin. Hence there is no scenario where "the community rejects XYZ". There is no "community". There are only algorithms and code. Every form of argument that starts with, "but then people will..." is a false one. There are no people involved here.

Yes, GHash.io had more than 51% briefly back in 2014 I think.  Then they agreed to stay below 40% and then a few years later shut down.  I am not sure if it was DDOS related, or just people leaving them due to having been close to 51%, but they've been gone for a while.

Still I don't think a 51% will actually happen.  literally everyone including miners are all out to make profit and with that much hash rate to carry out a 51% attack I think mining pools would be smart enough to use that enormous hash rate themselves to collect more mining rewards rather than trying to re-org particular blocks on the network. Take for example as of recent, September 2024, the total Bitcoin network hash rate is around 300-400 Exahashes per second (EH/s) when I last checked. To launch a 51% attack, an attacker would need to control at least 51% of this total hash rate.

Let's assume a total network hash rate of 350 EH/s (say a rough estimate). To calculate the required hash rate for a 51% attack:

51% of 350 EH/s = 0.51 × 350 EH/s ≈ 178.5 EH/s

So, an attacker would need to control at least approximately 178.5 EH/s to launch a 51% attack on the Bitcoin network.
Almost no one would want to waste such hash rate on an attack since there is a possibility that it would be aborted before it's success.

Which nodes? If it's some random nodes over the Internet the legitimate nodes would simply ban them for misbehaving and not following the protocol. Even if it's 80%. Bitcoin is sybil attack resistant for a reason.

If they take over several major exchanges? This would maybe cause some confusion, because legitimate users would then have problems to transfer from and to these exchanges. But nevertheless, it will be detected in a few blocks at most. Exchanges (these are real people, by the way) would warn users via other channels. Okay, let's say the hackers also take over all major social media sites. Nevertheless, the confusion will only last a few hours at most.

The most important thing is that you can't trick a legit node into accept a non-protocol compliant chain. What is possible is a hack of mining pools (see below).

A real 51% attack, i.e. mining real protocol-compliant blocks with real hashrate, can of course cause damage. That's undisputed. But creating such an attack only via "hacking" (i.e. without wasting money in buying hashrate) would need:

1) You would need to hack the nodes of the pools first.
2) You would need to hack then also the nodes of major miners, because once miners detect that there's something wrong (see my last post: even if there's no major reorg, it is quite obvious when a single pool or even an address is censored), they will change the pool.

Both pool owners and miners (above all, major ones) do pay people to monitor their systems. They would very fastly see that something isn't right, e.g. when they lose access to their own user accounts on the system. And chain analysis firms are very likely to cooperate with miners and warn them about more subtle attacks like censoring, because they will fear their business model not to work anymore if Bitcoin is heavily hit by the attack. (I see @franky1 addressed that topic too).

You can also hack the software but as it's open source this would also be detected quite fastly. And you will always have lots of nodes which will not upgrade to the infected version.

There are so many actors that would have to be "taken over" that it should be the most complex hacking attack in history by far.

I believe this to be borderline impossible, perhaps 99,999999999%, to succeed for more than 1-2 hours. Of course a short "takeover" attack could cause a dip in price and some double spends, but I believe this would not result in major damage, much less in censorship.

True miners won't put the source of their bread and butter in to chaos.  This will affect them more than any other else.  One example is Ghash.io, there is one point in time in 2014 where the mining company almost reach the 51% mining hashrate and it alarms the community, to be able to avoid to amass 51% hashrate they voluntarily reduce their mining hashrate to pacify the outcry of the community.


Or make a hardfork and return to the time stanp where the network is yet to suffer the 51% attack.  But obviously, this will dwindle down the trust in Bitcoin at least and at most there will be an instant 180 degree turn for most of the holders and believers and possibly Bitcoin will never be the same again.

The thing is that if everyone knows a 51% attack is happening and if the attackers were able to maintain their atttack, everyone would simply abandon the longest chain because it would then be corrupted.

The longest chain is considered the Bitcoin chain for the purposes of maintaining a consistent history when dealing with orphaned blocks. That doesn't mean the global Bitcoin community will just be forced to blindly follow a corrupted chain if a 51% attack occurred lol. Human beings are involved in the operation and use of Bitcoin, it's not just blind machines following rules. Those 51% attackers would quickly find themselves in 100% control of a completely useless blockchain and Bitcoin would keep going as normal. As soon as the 100% of honest miners switched away from the corrupted chain, the attackers would lose the chance to get the mining rewards they were hoping to get because the blockchain history they are using would be different from the blockchain history everyone else is using and so even if they kept running their chain they wouldn't be able to spend the money with anyone but themselves.

Now sure, they could keep doing the attack again and again, causing chaos for a short time, but they'd keep losing and burning huge sums of money for no monetary reward. Eventually they'd have to give up and it'd be an enormous financial ruin for the attackers.

not only that, the costs shown are just to do a blockchain annoyance of transaction inclusion/exclusion.. if he then wanted to mess with the multiple CEX markets he would need a separate budget(s) to then spend on CEX market(s) to try to crash the market(s). which the CEX(s) can then freeze the account instantly and seize the funds (or simply just deny the order, or ban access to the ordering feature)

Repeat: stop repeating this hypothesis like everyone else, and go make it at least a theory.

Repeat: people are ignoring the fact that it's not an issue about whether an attack is possible, but whether a PROFITABLE one is.

Repeat: ignore the reputational cost (you guys focus on financial only all the time).

You literally reply and ignored these points.

In your scenario, Russia hacks and gains control of all the mining servers. WOW. How long before these hacked servers get taken offline? Are they going to allow Russia to use that power to mine even 1 block? I guess in your scenario yes, because these powerful companies with 100s of IT staff and security owning the servers will just sit back and prove your hypothesis. They will never think to just pull one OFF switch to the power lol man, you really need to go and gang up with all the 100s of people who talk about all these fantasy stories and please convince someone to attack Bitcoin. I would love to see you guys do that seriously.

Actually, go for easier first, try do it to Dogecoin or something first. Maybe you can ask Belarus to help you hack a few Dogecoin mining servers, and come back and tell us all you proved you successfully attacked, made money, and own the new chain, and nobody stopped you because there are no people involved.

There is no Mining servers with Bitcoin mining to be exact.

Bitcoin miners can run their own Bitcoin full nodes if they are solo miners but time for solo miners gone a long time ago. Nowadays if you are small solo miner, you are only wasting your resources without bitcoin rewards from mining.

With big Bitcoin miners, they can run their own full nodes if they want to set up their own big mining farms or they can configure their ASICs to join available Bitcoin mining pools that have their own Bitcoin full nodes.

Fortunately Bitcoin network is decentralized and Bitcoin miners can easily config, re-config their ASICs to any mining pools.

Servers? No, they don't care.