> The point is that the police can't prove you do or do not remember a code. Consequently, they can't compel you to use that code. Also, they can't coerce you

> The point is that the police can't prove you do or do not remember a code. Consequently, they can't compel you to use that code. Also, they can't coerce you to reveal the code even if they can prove you know it. Confessions extracted under torture by inquisitors was a recent memory when the Bill of Rights was drafted.