PALS and Pakistan Part One - Introduction to Permissive Action Links

In the aftermath of September 11th, Pakistan has been thrust into a new relationship with the United States. Questions about domestic reaction to this relationship have given rise to fears of Islamic fundamentalist groups compromising the security of Pakistan's nuclear arsenal and even suggestions that the United States should prepare for possible military action within Pakistan to seize control over its nuclear weapons (Davidson and Global Security Newswire). Other commentators have suggested cooperative measures to improve the security of Pakistan's nuclear weapons. This paper will analyze one of these proposals: to provide Pakistan with Permissive Action Links (PALS) for their arsenal to prevent unauthorized use. Permissive Action Links, or PALS, are a technology integrated into nuclear weapons to force any potential user to enter an authorization code before the weapon can be armed (Bellovin). They were originally developed by the United States during the Cold War as a method of securing our systems from rogue commanders or Soviet infiltration. Little information is in the public record describing how PALS actually function, but the most recent model is the CAT F, which requires a 12 digit code for authorization (Bellovin). The system features include: a "limited try" system that automatically uses a detonator charge to disable the weapon if multiple incorrect codes are entered, a remote disabling system that allows the weapon to be rendered useless via transmission, and a multiple code system that accepts dummy codes designed to make cracking the code more difficult (Bellovin). The most recent pricing data for the system is from 1984, when the CAT D version cost roughly $50,000 (Bellovin). The newest versions are directly integrated into the weapon using a protective skin system. The system is designed so that any damage to the skin (in an effort to remove or bypass the PAL) would permanently disable the bomb (Bellovin). These features combined mean that any group that was able to obtain one of Pakistan's weapons would encounter great difficulty arming or using the device.