The biggest mistake is to draw a line between not willing to, not caring enough to and being unable to do it.
Just because China doesn't care that much about it it doesn't mean they wouldn't be able to launch an attack, just as how you can't say that for example the US won't be able to launch a full invasion of Cuba, the fact that they haven't doesn't mean they can't.

It is a thing about how much they are willing to lose or to pay for that, everyone said that the prohibition doesn't work and can't be enabled, the middle east would have a story to tell. If everyone caught drinking alcohol in the US during the prohibition would be hanged like in Iran I think the prohibition would have been a success.



The bad blocks will not be invalidated, they will just mine 10 empty blocks that will replace the last 8 blocks, then again stay hidden while good miners add the invalidated transactions in another 8 good blocks they again propagate 10 empty blocks denying again all the transactions. And while this happen all legit miners see their previous rewards destroyed and erased from history, how long do you think legit miners will be able to keep up the game?


Pray that there will never be one cause if it happens before the cost would be out of reach for even world powers we're f****.

Aha, sure. Good luck going back to the first 210,000 blocks, and reversing years of history. And not only that: good luck rejecting existing soft-forks, which were activated at certain block heights, and writing a chain, where those checkpoints will be in a different block numbers, or with different block hashes, without alerting thousands of nodes.

More than that: good luck reorging thousands of blocks, from more than one halving, and triggering all block explorers, and other databases. And also good luck triggering all pruned nodes, that they have to re-download the whole chain from scratch, and rebuild their database. Good luck doing all of that unnoticed, without a single topic on the forum saying "ALERT! HUGE NETWORK REORG!".

Technically? Maybe. But if you ever tried to mine 100k blocks or more, even in regtest, with minimal difficulty, on CPU, then you know, how slow it is on CPU, when you can mine hundreds of blocks per second. And imagine, that you don't have regtest difficulty, but mainnet difficulty. Even using "the longest chain" instead of "the heaviest chain" means, that your regtest experiment is 2^32 times easier to execute. But if you take into account the current chainwork, then guess what: collecting one million newly-created BTC in fees alone is much, much more profitable, than executing such attack.

To sum up: mining new coins on charity's address is easier and more profitable, than forcing exactly Satoshi's coins to land there.

1. Rejecting existing soft-forks, and re-activating them under new rules (or leaving them unactivated).
2. Rebuilding databases in a lot of nodes in the world, triggering a huge debug log report for all node runners.
3. Triggering blockchain redownload for many, if not all, pruned nodes.
4. Alerting a lot of full node runners, that they are back in "Initial Blockchain Download" stage, which will cause a lot of questions.
5. Deciding to increase the supply or not, by deciding, if some coins should be burned in the coinbase transaction, in OP_RETURN outputs, and so on.
6. Seriously changing the total chainwork, so it will produce even more detailed debug logs in all node runners.
7. Being blacklisted by a lot of nodes, because of exceeding P2P network traffic limits, and being marked as "misbehaved node" by most of the network.

And so on, and so on. If you want to experience it, then use your CPU, run Bitcoin Core in regtest mode, mine 800k blocks, and try to trigger for example 600k block reorg. Good luck. If you see, what happens, when you do it on your CPU, with minimal possible difficulty, then you can go further, if you are patient enough to observe it.

Once I mined something like 250k blocks in regtest. It took way too much time, to not be noticed, even if it would be some kind of public test network.

Edit: One more thing to note. Currently, developers are trying to kill testnet3. It is just a test network. It was resetted previously two times, and it is going to be resetted again. You can see, how many people are complaining about it. You can also see, how many people are complaining, where some altcoins are resetted, hard-forked, or changed without reaching consensus. Judging by that data, you can only imagine, how loud people could scream, if similar things would happen to the mainnet.

Even with fiat currencies, if you mess up with money, you can make a war. In the crypto world, people are even more focused on some values like decentralization, and all newspapers would be flooded by headlines like "BITCOIN HUGE CHAIN REORG" if you would try to even trigger more than 100 confirmations chain reorganization, not to mention more, like reorging beyond more than one halving, to get access to Satoshi's coins, and to not let them to be sent to Satoshi in the first place.

One more hint: there is two hours rule. Two hours is just 7200 seconds. By having five or six blocks with the same time, you can get something like 40k blocks. See? Only 40k blocks per two hours. If they are empty. If they can be easily verified in a fraction of second. If they are mined instantly, and you don't care about difficulty. For 400k blocks, you would need at least 20 hours. On localhost. With perfect network communication. With no missing transactions. With instant block validation, without bloated 1-of-3 bare multisig or other tricks.

See? In case of 600k block reorg, one day may be not enough to even share your great new history, written by the winners. Unless it will be empty, and you would say in your chain, that "Bitcoin was unused for the last 10 years, and all miners created empty blocks for that time".

Edit:
Then you will have an altcoin.

In case of Value Overflow Incident, the community noticed the flaw, and patched it, before even Satoshi released a new version. Later, he only confirmed that patch, it was applied much earlier by the community. And everything was fixed within 5 hours or so. When the network was in its infancy, and it was not as popular as today. When you didn't even have block explorers as smart as today.

https://en.bitcoin.it/wiki/Bitcoin_is_not_ruled_by_miners

Good luck convincing users to run your software. By starting from zero users, it is hard to compete. It is like saying "let's ignore Microsoft, we will deploy our own system, and we will legally force everyone to uninstall Windows". It is simply not gonna happen. What do you want to do? Shut down all computers, rejecting to run your software?

There was a short period of time, when BCH had more than 50%. Does it mean, that it was Bitcoin for a while, and they suddenly stopped being Bitcoin?

Sure. But you cannot ignore some existing product, and say "hey, people, I did it better, just buy it!". Full node runners can decide, that they don't want your new product. What then? Even if you have 51%, or even 99% computing power, it doesn't matter, if you don't have any customers.

The same I could say about "backward compatibility". You cannot release something completely new, out of thin air, ignore all existing solutions, and say to everyone "just try this new thing, because I want to sell it". You can have 99% computing power, but nobody would care, if you would produce strictly invalid blocks, containing garbage transactions, that cannot be properly handled by the current software.

Miners are mining blocks. They are selling this product to the users. Even if they have 99% computing power, it doesn't matter, if there are no buyers. They are not producing new blocks, because it is their hobby, and they want to kill time. They want to produce something, which users are going to accept.

It is not. But you cannot break backward compatibility, because you feel like it. In the same way, you can try to write some new operating system, or some new programming language, and say: "I don't want to use C". But now, C is no longer a language. It is now a protocol. And the same with Bitcoin: it is not just a coin, it is also a protocol. And if you want to bring existing nodes to your own network, then you have to talk to them, by using this existing protocol, or they won't listen, and you will reach an altcoin, if your coins are not compatible, and if people will be unable to convert BTC into coins, accepted in your network.

You could be surprised, how many different versions are currently running in the network. You don't have a situation, where 100% of the network is running the same, and latest version of Bitcoin Core. It is not the case. There are different versions, there are different configurations, and there are different kinds of nodes.

For example, you have some nodes, operating mainly on UTXO set, called "utreexo". Good luck trying to convince them, that UTXO-based model should be replaced by account-based model, or something like that. You have to stay compatible, with what we have today, at least to some extent. The same on this forum: you have to use English, and not "your own home-made natural language, because existing languages are bad". By saying "I am going to ignore the database", you are saying something like "I am going to ignore the existence of English, and write it in Quenya". Good luck convincing forum users to stick with your protocol.

"You" are a software developer, trying to introduce backward-incompatible changes, and thinking, that by having 51%, "you" can change the way how existing software works. "You" cannot. Nodes simply won't understand "your" messages, if "you" are going to "ignore the database".

By reading the protocol. If you have "tx" P2P network message, then you can send transactions. In some strictly-defined format. Not just "arbitrary data, no matter what". You have to stick to the protocol messages: https://en.bitcoin.it/wiki/Protocol_documentation

If you produce something unusual, it will be instantly rejected, in the same way, as if you speak Quenya, your content will be rejected by English-based community.

For example: we had "checkorder" message, when we had Pay-to-IP features. Now we don't have it. And you can have 99% hashrate, it doesn't matter, by having that, you won't reintroduce Pay-to-IP messages to the protocol, if your peers won't understand it.

By having code, which is responsible for detecting that. If you start broadcasting bad messages to the network, then other nodes will automatically execute "setban" command on your IP, for example up to 24 hours. If you try to execute 600k block reorg, then first, long before that, people will need to download and verify your blocks (and then, they will notice that something is wrong). But even if they don't, then by trying to wiping away 500 GB of history, you will trigger all kinds of protections, related to allowed data transfer in P2P network, so either you stick with the bandwidth, allowed by other nodes (and then it takes time to share those blocks), or you send more than allowed, and other nodes will ban you automatically, or disconnect from you for the next hours, and try other peers automatically.

By playing the game of trust, and sticking to some simple, universal rules: https://ncase.me/trust/

There are many CopyCat nodes, which can win the war in the long term. You can try to introduce some new node type, and compete with CopyCat. If it will be successful, then it may be adopted, and used by the majority of users. But if your node is a Cheat node, producing incompatible messages, then it will quickly lose the game, by being banned by most of the network, and having no peer to connect to, for the next 24 hours.

Nodes are judged by their behaviour. If you send invalid P2P message, you will first receive some kind of warning, then some short ban, and then it can escalate, up to 24h ban. You can test it in regtest on localhost, if you want to know, how exactly debug log file will look like.

See "setban" command, and CTRL+F or grep places in the code, leading to those parts.

https://github.com/bitcoin/bitcoin/blob/master/src/banman.h#L28

Just read "banman.h" and "banman.cpp" files, to find out.

Why? If you connect to your own server, you can trust it. It is your server, your node, the same entity, the same party. You can also trust localhost. There are many things you have to trust, to have some basic computing ability. For example: you have to trust, that your random number generator is "random" enough. If it is not, then all of your private keys could be compromised.

And command-line options like "setban" or "invalidateblock", or even "preciousblock" are there for what? Because developers had nothing better to do with their time?

Obviously, most nodes run on autopilot, for most of the time. But: there are ways to grep debug log, and catch some unexpected behaviour. Even when some mining pool violated sigops limit, it was quickly noticed, and you even had forum topics about it: https://bt.irlbtc.com/view/5447129

See? Some people are reading those logs. And in the Open Source world, it is normal to have some eyes, watching some logs, reading some code, and talking about what they can see, if they observe something unusual.

👍

Many plebs like me, and newbies, forget that cryptocurrencies are more than the technical layer. It's actually about the social layer. Visualize a situation when a state-level actor successfully 51% attacked Bitcoin, and the Core developers, the economic majority, and the community in general had consensus to fork Bitcoin making the other side of the fork a centralized Govcoin network. Haha.

Plus what would probably happen is those bad actors that attacked the network will probably come back and mine honestly to earn Bitcoin.

¯\_(ツ)_/¯

But what does that actually mean? "Ban the good nodes", and cause a fork in the network? Which side of the fork does everyone actually believe that will gain the support of the Core Developers, the Economic Majority, and the community in general? The centralized Govcoin, or Bitcoin?

Why exactly do the "Core Developers" matter?

Are the Core Developers the people who... control Bitcoin?

If that were the case, then Bitcoin would absolutely be centralized and any government could control Bitcoin simply by controlling these "Core Developers". These Core Developers could be threatened with jail, for instance, if they didn't change the code to enact changes some new laws demanded.

But that's not the case. Bitcoin is not controlled by a central committee of any kind: it's an algorithm. What controls Bitcoin is the majority of the nodes/hashrate on the network, not any identifiable human beings per se.

Hey folks, so after a lot of (great!) discussion here, I'll try to summarize the key conclusions of this thread:

1. The short answer to the thread's question is yes, China (or similar) could take control of Bitcoin if such an entity were so inclined.

2. It would be done by either compelling through law, or taking over by clandestine means, existing nodes on the network.

3. There are current two centralized, identifiable companies that control over 50% of the Bitcoin hashrate, so an effective takeover of Bitcoin would only require control of two entities, not the "thousands" that many probably think it would require.

4. While it's true that the motivations of such an attack are not readily obvious, I actually don't think we've spent that much time here working through the scenarios, either. Taking over the Bitcoin network would be a "hostage situation" wherein major holders would want, more than anything else, to maintain the value of their holdings.

5. The principle protection against this kind of attack--and indeed, the primary defender of the Bitcoin network--is none other than the United States federal government, without whom Bitcoin would be fodder for every manner of state actors attacking it. The only thing stopping such an attack right now is fear of reprisals from the US and its allies.