If your threat model is someone stealing and cracking your private key, you really ought to be more worried that they are going to use their time machine to go back in time and kill your mother.
Both actions happen at the same time, someone phishes you, captures your input and they have the password for it as well. Now that they've got a shell on your box IP address restrictions are bypassed as well, as is port knocking. This is completely plausible, time machines are not. I read a (private) incident report very recently where half a company had their devices spear phished in order to gain access to a single internal server.
Comments
If your threat model is someone stealing and cracking your private key, you really ought to be more worried that they are going to use their time machine to go back in time and kill your mother.
Both actions happen at the same time, someone phishes you, captures your input and they have the password for it as well. Now that they've got a shell on your box IP address restrictions are bypassed as well, as is port knocking. This is completely plausible, time machines are not. I read a (private) incident report very recently where half a company had their devices spear phished in order to gain access to a single internal server.
Oh, someone capturing your private key's passphrase is something to be genuinely worried about.
Someone brute forcing said passphrase? Yeah no.