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randomran01234 | 3 years ago

Why? PoW can only afford to be attacked twice. It even has a name: “spawn camping.” In proof of stake, this is pretty easy to defend against repeatedly.

https://vitalik.ca/general/2020/11/06/pos2020.html

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rufusroflpunch|3 years ago

If you are accepting that the network can hard fork to change the hash algorithm, then why not accept that they can do a soft fork to blacklist UTXOs or any one of who-knows-how many possible defenses? Changing the hashing algorithm is a nuclear option and probably not necessary in the astronomically unlikely event that someone managed to get 51% of hash rate for any amount of time.

edit: Blacklisting UTXOs is entirely possible as I mentioned, and as I said, it should be achievable by soft fork. This would be the proof of work equivalent of slashing. I have a hard time believing Vitalik doesn’t know this. Is he being dishonest? I don’t know.

randomran01234|3 years ago

Good question, I’d be interested to hear a core dev’s thoughts on this.

cowtools|3 years ago

I don't understand how PoS changes this. Also, that blog post does not consider CPU-mined PoW which is unprofitable for miners and sustained attackers.

randomran01234|3 years ago

In PoW, if you control 51% of mining the users can defend by switching to another hash algorithm, meaning the attacker needs to re-buy a lot of new hardware. If they’ve anticipated this, and attack again with new hardware, there is not much further defence. In PoS, users can coordinate a soft fork to burn the attackers funds, each time they re-attack the chain, until they eventually run out of capital.