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Satoshi really downplayed 51% attacks in his/her original whitepaper[1]:

> The incentive may help encourage nodes to stay honest. If a greedy attacker is able to assemble more CPU power than all the honest nodes, he would have to choose between using it to defraud people by stealing back his payments, or using it to generate new coins. He ought to find it more profitable to play by the rules, such rules that favour him with more new coins than everyone else combined, than to undermine the system and the validity of his own wealth.

Apparently he didn't realize that coins could quickly be transferred to other crypto and not held, so who cares about the value of the stolen goods.

[1] https://bitcoin.org/bitcoin.pdf



I think it's probably fair to say that he/she did not anticipate people spinning up a whole bunch of crypto-currencies and that those crypto-currencies would be worth something. How many coins are out there that are worth millions of dollars to people speculating? I certainly wouldn't have given that idea credence at the time Satoshi wrote the original whitepaper.

I personally thought that BTC would either be successful (in that it would be a useful currency) or that it would tank. I did not anticipate people dumping piles of money into it to speculate on its value. I certainly did not anticipate a bunch of wannabe coins sitting on millions and providing practically no value to anyone.

It's a testament to the number of people who are desperate to get rich. I probably should have taken a cue from the lotteries...


I'm pretty sure he did.

It's not like we don't have dollars and euros and so on, and silver and gold in the past.

> I did not anticipate people dumping piles of money into it to speculate on its value.

98% of trading in euros and dollars is pure speculation.


Yeah in the next couple years I'd expect to start seeing smaller PoW chains wither away due to attacks like this and exchanges starting to have prohibitively high conf times as they'll need to protect them selves from attacks like this.

Merchants are probably fine.


The point is that stolen goods cost as much as mined goods, so why would an attacker prefer to steal?

(Unless they are trying to vandalize the ecosystem)


The calculus to steal compared to mining is actually much cheaper. Just briefly hold 51% while you double spend some massive wallets.


Assuming the counterparty is an idiot and accepts your huge payment with a very low amount of confirmations.


But wouldn't the long-term honest mining be more profitable than a single hit and run? Kinda the same reason that when you go to a restaurant the restaurant owners almost always exchange food for money rather than rob you and leave town forever. If you own a restaurant it's generally more profitable to run it honestly than run away with a one-time dishonest payoff.


Not if it destroys the credibility of a rival coin, which I suspect could be the case here. Many in the "real Bitcoin" community call Bitcoin Cash a fraud because its existence reveals the specious value of their "real" cryptocurrency.

Executing a double spend attack on Bitcoin Cash would be a massive success for Bitcoin owners. Same goes for Bitcoin Gold.

You could even create a mining pool/network - let's call it CoinFucker - where every now and then the pool's resources were diverted to attack a rival coin. Doing so damages that coin's reputation, and in doing so reduces the competition. This would be a great way for the majority of mining/computational power to squash would-be rivals.


I'm not sure in this specific case it would make sense for Bitcoin users. Unless you are already involved in cryptocurrencies, I'm not sure the average person is going to differentiate between "Bitcoin" and "Bitcoin Gold" -- the negative impression of "Bitcoin Gold hit by attack" is going to reflect on the original Bitcoin.


Because you don't have to pay for the long term mining equipment and instead can just rent them from AWS/GCP/Azure for the attack.

If you did buy them though, you could attack cryptocurrencies one by one stealing money from a bunch of different ones.

I think both situations would be more profitable.


Depends on if you feel that the crypto would continue to have value in the long term. If you've amassed that much power (or are close to it), and you didn't feel the coin was going to hold value long term, why not?


You cannot mine all kinds of coins at same time, so why not be honest in one network and hit and run in another?


The notion that there would be other cryptocurrencies was just not part of the worldview, back then.




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