A 51% attack only allows you to (1) censor transactions for a short time, and (2) double-spend. The first part is a mild nuisance. The second one can be retaliated against off-chain, which puts the attacker (who must be a large entity) at great risk in the real world.
On the growing risk of the 51% attack against BCash
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Re: On the growing risk of the 51% attack against BCash
#12OK, this is describing a 51% attack. And who would engage in this 51% attack? The miners? The miners are one of the biggest groups that SUPPORT Bitcoin Cash, so I find it unlikely that they would spend millions attacking it. Anyway. It matters not. The people that want Bitcoin to be a settlement layer are free to spend 50$ per transaction to use Bitcoin, and those of us who want to use it as an actual peer to peer el…
Anyone who's mining Bitcoin could switch to Bitcoin Cash and work to perform a 51% attack. > BCash shares hashing algorithm with Bitcoin. That means any hashing power on the Bitcoin network can work on BCash network. And there is typically 10 times more miners mining on BTC, than on BCH because of the difference in the price and minning fees.
And which miner SPECIFICALLY would do that? There are only like 7 major mining pools. Which of those 7 do you think would do an attack?
The miners were the ones who helped create Bitcoin Cash. Why would they attack it?
The miners are the largest supporters of big blocks, so it make no sense that they would attack the thing that they helped launch.
Also, people don't seem to realize that it is already possible to do a ~20 percent selfish mining attack. And yet we don't see THAT happening...
These attacks aren't realistic in practice because it would be immediately obvious that something is happening, and the miners would lose all their money as Bitcoin crashes.
Re: On the growing risk of the 51% attack against BCash
#13The was a long winded explanation of a 51% attack lol. Was the author just talking about hashrate switching? Any solutions for exchanges or merchants such as just increasing the confirmations required? Any interest in bitcoin cash changing it's algorithm?
> Any interest in bitcoin cash changing it's algorithm?
I doubt it. One of the reasons BCH hardforked was so large mining pools could continue to take advantage of Asicboost, a patented approach to Bitcoin hashing that provides a 20-30% speedup.
Asicboost is essentially taking advantage of a flaw in the original Bitcoin algorithm which leads to slightly predictable hashes. Segwit fixed this problem, nullifying their patented advantage.
All of the vocal BCH supporters are involved with large sha256 mining pools. I think it's very unlikely that they'll elect to change algorthms.
Re: On the growing risk of the 51% attack against BCash
#14Is it possible it's already happened? I have no idea what the mining breakdown looks like - but I'd imagine it's only a couple players mining BCH. I'd think you could rewrite the chain at will pretty much.
We would see two chains forking of a shared block with a significant length (~10). Unless you count Bitcoin Clashic[1], there's no proof of that
Re: On the growing risk of the 51% attack against BCash
#15A 51% attack only allows you to (1) censor transactions for a short time, and (2) double-spend. The first part is a mild nuisance. The second one can be retaliated against off-chain, which puts the attacker (who must be a large entity) at great risk in the real world.
> The second one can be retaliated against off-chain.
What do you mean?
Re: On the growing risk of the 51% attack against BCash
#16A 51% attack only allows you to (1) censor transactions for a short time, and (2) double-spend. The first part is a mild nuisance. The second one can be retaliated against off-chain, which puts the attacker (who must be a large entity) at great risk in the real world.
Yes. A 51% attack is a popular whipping boy. It's not as dangerous as it seems.
The price would tank, for sure. But your money won't be gone. And eventually when the attack dies down you'll get your wealth back.
However, it remains a very interesting way for governments to completely destroy Bitcoin. It's the only way, and they have to do it now before centralized, dedicated mining facilities come online. It would disrupt the price enough and scare away enough people that the threat BTC poses will vanish, at least for awhile. And that will discourage miners from setting up facilities, such that the governments can just beat them again if they have to.
But it's already almost impossible.
The difference is intent. It's not really much of a problem for a miner to have >51% share. They're there to make money. And Satoshi pointed out they'll probably just keep mining rather than devaluing their own wealth.
But an organized, worldwide governmental campaign against cryptos would be another matter.
Re: On the growing risk of the 51% attack against BCash
#17Not happening. ANT Pool has a huge investment in Bitcoin Cash and would swoop in with mining power to protect their investment.
Please re-read the post, because you don't understand.
The 51% attack is carried in secret. Noone has any way to know if it is happening until the longer chain is published. And after that, it's too late already. Someone could try to catch up with (not anymore secret) longest chain, but the damage has been done - the state of the network has already changed. Actually switching it back is only adding salt to the wound. Noone would trust that coin again anyway, and it is worthless to try to rescue it.
AntPool is busy mining Bitcoin, because it pays better:
so it can't constantly police BCash chain by over-provisioning it.
Re: On the growing risk of the 51% attack against BCash
#18Not happening. ANT Pool has a huge investment in Bitcoin Cash and would swoop in with mining power to protect their investment.
How would they protect it after a double spend occurred?
Re: On the growing risk of the 51% attack against BCash
#19The spectrum is really marvelous. It's amazing to see how many different kinds of people, with many different motivations, will waste their time on speculative crypto-coins.
Re: On the growing risk of the 51% attack against BCash
#20I like the math and theory on this. But really why would someone who's making millions on the status quo risk tanking the market for a one time gain? Seems unlikely.