For nearly 20 years, the secret code to authorize launching U.S. nuclear missiles, and starting World War III, was terrifyingly simple and even noted down on a checklist.
From 1962, when John F Kennedy instituted PAL encoding on nuclear weapons, until 1977, the combination to fire the devastating missiles at the height of the Cold War was just 00000000.
This was chosen by Strategic Air Command in an effort to make the weapons as quick and as easy to launch as possible.
The Permissive Action Link (PAL) is a security device for nuclear weapons that it is supposed to prevent unauthorized arming or detonation of the nuclear weapon.
JFK signed the National Security Action Memorandum 160 in 1962 that required all nuclear missiles to be fitted with a PAL system.
So they simply left the security code for the weapons as eight zeros, getting around the security safeguards.