[rayiner]

I don't think it's a great analogy, because translating documents requires a wholly different level of mental involvement than simply recounting an encryption key. Note that even fishing out and providing a regular key requires some degree of mental involvement.

[derekp7]

What about providing information such as what language the document is written in? Of course, the real equiv. is if the document is written in code, then can you be required to reveal the secrets of the code?