Well yes. But in that case a password is security through obscurity. I struggle to think of any security scheme that doesn't rely on knowing something the atta

Well yes. But in that case a password is security through obscurity. I struggle to think of any security scheme that doesn't rely on knowing something the attacker doesn't. So unless you want to write everything off as STO you need to introduce some nuance into the conversation. IA seems to me to be a useful nuance.