If the point is just to have a fake classified document for an example or illustration, I'd put a fake organization name on it. (law.stackexchange.com)
The exhibition presents 29 large - scale color photographs as previously classified documents. (ccrjustice.org)
Back in 2006, an Australian Internet activist launched a website with the goal of sharing classified documents globally by making it impossible to trace sources. (maddwolf.com)