> For any locked door, you need more than one key and they should be independent. If you have independence, they serve as backups for each other. For any locke

> For any locked door, you need more than one key and they should be independent. If you have independence, they serve as backups for each other. For any locked door, you need a key for day-to-day use; beyond that, you need to know a way to contact a locksmith or how to use a crowbar yourself, and have a way to eventually prove you're authorized to access what's behind those doors. All those real-world analogies in crypto tend to miss one critical thing: in real world, things break, and people make mistakes, so for any security system, there exist ways to recover from failure or mistakes, and ways to recover from failures to recover, and so on. Yes, this means you may spend a couple hours talking to the police afterwards, but you won't be forced to camp outside of your apartment on a cold winter night, because you've left your keys at work.