tangles has it right on the head, here.
/specifically, you probably need it to say certain things about foreground and background knowledge really, but I've signed one before with a Norwegian company that is only 3 lines long and says "I won't tell if you don't" or words to that effect. So that will do.
( the mighty badger Aphrodite, on a bar stool, by your side, Wed 15 Aug 2012, 11:08, Reply)