Comment by Tossrock
14 years ago
When I first heard about the Bell-LaPadula model ( http://en.wikipedia.org/wiki/Bell%E2%80%93LaPadula_model ) in my security class, it was pretty eye opening, especially the notion that once you're given a certain level of access, you can no longer write at lower levels. I think it might explain in part the explosion in the amount of classified material generated each year.
Yeah, that model is more or less what's in use. Except the real-world version is a bit more complicated and messier (and more confusing). But the principle is all the same. Read goes down, write goes up.
You can move information down only if the information is at the level you are moving it to and it's been properly signed off.
e.g. something that is marked Secret, but written to a Top Secret system, can be moved back down to the Secret system)