In Germany is rule is simply that you are not required to do anything to actively help our own prosecution.

They want to take your fingerprints? You don't need to help by lifting your arm. They want you to open a safe? No need to tell them the combination, through they will crack it open if you refuse. Same with encryption keys, you don't need to say anything. Telling the truth? As the accused you're allowed to lie in court however you want.

If you do get sentenced you can get a reduced sentence if the court thinks that you've been cooperative. But you can never get punished simply for the fact that you didn't help with your own prosecution.