All software security depends on hardware security.
If the hardware can be stolen or surreptitiously replaced, secure software will not help. When computers filled a room, stolen computers were not a big problem. Now that laptop and palmtop computers are the fastest growing market, physical security is at least as important as software security. Most of these safeguards are required for the DoD's System High and Compartmented Mode Workstations, which are briefly discussed in a later section. Communications interception is discussed in Chapter 9 .