For example, if your voiceprint were required to unlock your phone, but not a particular passphrase. Could you be compelled to speak (or just recorded speaking) general statements in order to unlock?
I'd bet that law enforcement will be routinely using backdoors to gain access to our devices long before the laws that protect us from giving up a password are changed.
This is practically impossible. IMO it has been impossible for as long as phones have fused the decryption key and the screen unlock key into the same thing. (Some older Android ROMs let you have separate unlock and deception keys; does anyone know of any that still do?)
Either you choose a strong encryption key, in which case you have to spend a ton of time typing it in every time you want to unlock your phone, or you choose something easy to type in which case the key becomes easy to crack.
And in either case you have to do it over and over again in front of other people or security cameras constantly recording you.
> And in either case you have to do it over and over again in front of other people or security cameras constantly recording you.
That's partly prevented by having keys randomize their position on the screen so that your movements don't give away your code, and also by occasionally changing your password. Obviously if a camera is looking directly at the screen while you enter your password you're probably screwed.
I don't believe I ever claimed that.
> I'd expect that a longer password would only increase your security but that even the shortest password wouldn't leave the data encryption trivial to crack.
How short are you talking? Most people do like 4-6 digits. That's not going to protect you against anyone brute-forcing keys on the raw encrypted data. Your only real hope is the TPM holding the real key and being physically secure, which you have no way to ensure. And that still fails due to cameras etc. as mentioned.
> That's partly prevented by having keys randomize their position on the screen
That's almost security theater. It really only protects you from laymen, not state actors. It forces you to use numeric digits if you want that, which itself makes your key much weaker.
> Obviously if a camera is looking directly at the screen while you enter your password you're probably screwed.
Which is guaranteed to happen at some point when you're in public.