Permissive Action Link
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A Permissive Action Link is a security device for nuclear weapons. The United States Department of Defense definition is:
| A device included in or attached to a nuclear weapon system to preclude arming and/or launching until the insertion of a prescribed discrete code or combination. It may include equipment and cabling external to the weapon or weapon system to activate components within the weapon or weapon system. |
In 1960's, the combination locks were installed on the Minuteman ICBMs. However, the Strategic Air Command in Omaha worried that in case of need the codes would not be available, so they quietly decided to set them to 00000000; checking this combination was even present on the launch checklists. This was not changed until 1977.
The PAL or PAL-like devices have been portrayed in various settings by the entertainment industry, such as in the computer game Metal Gear Solid, the motion picture WarGames, and the television series 24 season 4.
[edit] See also
[edit] External links
- http://nuclearweaponarchive.org/Usa/Weapons/Pal.html
- http://www.cs.columbia.edu/~smb/nsam-160/pal.html
- http://www.sandia.gov/50years/answers04-05-99/answer1b.htm
- The JCAE and the Development of the Permissive Action Link
- Keeping Presidents in the Nuclear Dark
- Security Engineering, Chapter 11: Nuclear Command and Control, Ross Anderson, ISBN 0-471-38922-6
