Yes, I've seen that episode of Game of Thrones too :) First, consider the requirements to set such a trap. The authors of the document need to be actively conc

Yes, I've seen that episode of Game of Thrones too :) First, consider the requirements to set such a trap. The authors of the document need to be actively concerned about a leaker, and to be OK with the document itself being leaked as long as they catch the culprit - at the same time, they need the document to be juicy enough that it will be leaked. They need to share the document in such a way that no two of the suspects will be able to compare notes, otherwise the jig is up. So no putting the file on a common internal resource (unless the server can stealthily serve different versions based on the user's login data); no attachments, else a reply all / forward would reveal the trap; no collaboration; no physical office where two suspects may see each other's copy. Is that still possible? Yes. But a _lot_ of times it won't be possible, and the would-be leaker will know it's not possible. It's much more likely, and makes much more sense, for critical documents to be shared in such a way that the users _know_ they are fingerprinted, and won't leak them. IIRC, major Hollywood studios do that with their film scripts. Second, what if the _key phrases_ are slightly altered in each version? Or hell, if your bosses want to finger you so bad, what's if they changed a small factual detail in each version? Then even the journalist quotes would reveal the leaker.