It is easier to ensure absolute security of the transport layer and the physical facilities the computers are in, as opposed to designing absolute security of e

It is easier to ensure absolute security of the transport layer and the physical facilities the computers are in, as opposed to designing absolute security of every application. The DoD runs its own worldwide IP network called DISN, on top of which many compartmentalized networks run. Check out http://upload.wikimedia.org/wikipedia/commons/6/6f/Intel_GreenDoor.jpg http://upload.wikimedia.org/wikipedia/commons/6/6f/Intel_Gre... for a visual example.