IIRC there are some historic high court rulings setting a precedent that detaining a defendant for not furnishing some information (combination to a lock) viola

IIRC there are some historic high court rulings setting a precedent that detaining a defendant for not furnishing some information (combination to a lock) violates their protection against compelled self incrimination / right to remain silent but if it was a physical object (key to a lock) that did not necessarily voilate same rights. This has now led to digital age cases where the prosecution suggests a password should be analogous to a key, not an idea. On a quick search, I couldn't find the relevant cases or discussion...