Permissive action link

A Permissive Action Link (PAL) is a security feature designed to prevent unauthorized use of nuclear weapons. It acts as a form of electronic lock that restricts the ability to arm or launch a nuclear weapon unless the correct codes or authorizations are provided. PAL systems are integrated into the design of nuclear weapons and may involve various technologies, including: 1. **Mechanical Keying**: Physical keys or mechanisms that need to be set to allow the weapon to be armed.