Correct. The “have combination in head” is directly analogous to encryption key. But they are allowed to open the safe by other means.

In the UK forgetting a password is not a defence.

TFA, and my above comment pertain to the US.

The UK's laws to compel people to give up passwords seems to make it a de facto crime to forget one's password. Worse yet, it seems like it's illegal to possess random bytes on your devices. I wonder if the UK would change course if people started emailing random bytes to politicians and other supporters of this law, while giving tips to law enforcement that these individuals are coordinating criminal acts over encrypted communications.

I know.

But ... If you're going to compell someone to give up the contents of their mind under threat of being found guilty if their mind isn't working properly, you may as well just do away with trial.

IOW, if you're going to compell speech, just compell the suspect to confess; it's the same thing.

> If it's locked with a key, not a keypad or combination lock, they can force you to give the key. The distinction is that the former is a product of the mind, while the latter is a physical object. Furthermore, what if you forgot the combination?

Sounds a bit silly. The location of the key is "a product of the mind." What if you forgot the location of the key?

IANAL but you could likely successfully claim that you forgot where the key is, exactly because that's a product of the mind. If they have evidence that you do actually know then you might be compelled to hand it over, though.

If law enforcement has a warrant to search your safe, they could presumably expand that search to the rest of your house if you forgot where the key is. The core distinction is that the key is a physical object, it exists somewhere even if you forgot where it is. By comparison the combination is a product of the mind. The only way to retrieve it is for someone to talk to the police (which they have a constitutional right not to do).