Can You Share a Passphrase on a Hish Key Between Two Machines?

You can publish a key to a completely unprivileged user account that can't actually see, let alone right to anything of importance on the system. And when you ar sink to the demon, you can still connect over nesesage tunnel. However, what you'll have access to is all the files that the demon has access to, not necessarily that user. Most people realistically, should be more concerned about getting owned.