The degree to which the console, keyboard, and monitor of a computer can be physically accessed determines the level of system security. This is a common back door opening to an intruder. To implement physical security, organizations often use receptionists, security guards, physical keys, combination or electronic door locks, and other access controls. Train staff to log-off workstations during breaks and meal times. Destroy sensitive documents, including disks, when no longer used.
Sophisticated tools can reconstruct files supposedly erased from a disk.
Only destroying the disk itself guarantees the destruction of the data it once contained. Store digital keys on smart cards, not on disks. Keep passwords secure. Avoid writing passwords down, then sending them through electronic mail or placing them in messages that are archived or incorporated in group discussion systems. Do not write PINs on ID cards.