> fork the chain at a snapshot before the attack, patch the protocol, and call that Bitcoin?
It won't work. The only way to authenticate who ones what coins is with signatures. If the signature algorithm is broken, you can't tell who the original owner is to move the coins to a safe signature algorithm.
You need to more to safer signature algorithm before the break, after the break it is game over.
> It’s worth remembering that Ethereum forked for much less
Ethereum could simply return the coins to the original owners. If the signature scheme is insecure, returning the coins just means the attacker can steal them again.
It won't work. The only way to authenticate who ones what coins is with signatures. If the signature algorithm is broken, you can't tell who the original owner is to move the coins to a safe signature algorithm.
You need to more to safer signature algorithm before the break, after the break it is game over.
> It’s worth remembering that Ethereum forked for much less
Ethereum could simply return the coins to the original owners. If the signature scheme is insecure, returning the coins just means the attacker can steal them again.