there are a bunch of things that could be added at the protocol level to solve the 51% attack issue to some extent and i believe some altcoins have done some stuff in this area although i'm not really following them closely.

for example a simple solution could be adding a simple rule that prevents any block that is n blocks deep to be reversed. for example if the head is at 100 then block 95 and lower would be irreversible even if 100% of mining power was owned by one entity.

changing PoW algorithm is also a solution as it was mentioned but i don't think it can be considered an actual solution, it is more like sweeping the problem under a rug. the problem doesn't go away, it is simply postponed and there is a good chance that it becomes a lot worse because if we change the algorithm the richest miners or the hardware producers could invest a lot of money buying equipment mining the new algorithm and if before we had 51% of hashrate owned by one pool by then we have 80-90% of hashrate of new algorithm owned by one farm.

That is correct. Satoshi actually briefly mentioned the fact that a miner would gain more by being honest than if they were to attack the network. I doubt it would be easy to solve it on a technical level without compromising the trustless and decentralised part of Bitcoin. I would love to read up on solutions that could potentially do it without compromising them but I've yet to come across any.

Yes that's right. I did read that part where Satoshi mentioned that if any party did get to implement the 51% attack successfully and do try to reverse a transaction or chain of transactions  then the cost of reversal process would itself be so heavy that they would rather choose to continue mining in the longest chain rather than initiating the reversal process.
This will force the miners to remain honest. So the point of doing a 51% attack is actually pointless.

"Temporary-coordinated-control", and what? For one double-spend, which will be rejected by the community/network? They'll be rewarded WITH BITCOINS if they simply mine.

Plus your other debates has never, and WILL NOT happen.

It's not only the incentives that keeps the network together, it's also the cost that adds to the risk, which also adds to the Game Theory aspect.

Would you attack the network, and pay for the cost to destroy the thing that enriches you, or simply be honest and cooperate with the network to enrich you?


OR rent the hashing power, attack, pay for the rent, enrich themselves.

I see the troll believes someone will take the risk for ONE double spend in Bitcoin. The window to 51% attack Bitcoin has closed.

Not quite true. It has been discussed lately and an ultimate solution has been proposed: put a cap on the depth of chain-reorg attempts.

it is controversial though: implementing finality in PoW is not welcomed by many of the core devs of because theytraditionally believe in a booting from the genesis idea, aking it as a measure of how trustless the system is or at least looks like. Once the blockchain is finalized in some heigth, individuals have no strong incentive to validate the whole history to become convinced about the state of the machine individually, it is frghtening for many people. Obviously, it turns to be more of a philosophical debate about what trust means and questions like 'is it possible ever to get rid of the social aspects of a monetary system?' Believe it or not it is considered as a Satoshi tradition the idealized bitcoiner who does not trust, verifies! A mathematical notion of a timeless, alone entity called individual user who is surrounded by a bunch of thieves and scammers and adversaries and the super hero fights with all of them by verifying the history of the blockchain they propose from day one, the genesis block.

My point: it is not a pure technical hurdle because the suggested cap would fix it easily, rather it is a political/philosophical debate.

Will "crush the price" truly "kill Bitcoin"? I believe, not. Plus they can "crush the price", it will be a golden opportunity for us. The wiser move would be to HODL.




That will NEVER happen.

The troll's debate is not about a 51% attack.

According to this article by the end of 2018 governments all across the globe had confiscated about BTC 453,000 i.e. 2.6% of the global supply at the time.

https://www.theblockcrypto.com/genesis/2944/analysis-the-u-s-has-seized-nearly-200000-bitcoins-to-date-global-confiscations-are-up-to-453000

Looking at CoinMarketCap the last 24h saw a trading volume of about BTC 3,000,000.

So looking at these numbers the global government holdings of Bitcoin are barely enough to cause a market dip for maybe a day or two, so... just another Tuesday when it comes to crypto.

Of course that was 2018 so maybe the governments already increased their stashes since then.

Except they didn't even held onto the aforementioned amount and have maybe a tenth of that left so like 0.2% of the current global supply.

¯\_(ツ)_/¯



"They"

Sure.

It may be able to stop a 51% attack but it also introduces a chain split attack, someone can just mine the number of blocks N needed to lock the rolling checkpoint, broadcast it to several nodes as soon as the main chain hits N blocks after the block with transactions they want to mess up, and the network will be split in half with no way to put it back together as a consequence of how rolling checkpoints work.

51% attacks are more of a practical problem to small altcoins (e.g. bcash), than a coin with exahashes/s total hashrate like bitcoin.