Boeing has delivered upgraded cryptography devices to Northrop Grumman and the US Air Force for the intercontinental ballistic missile (ICBM) system.
The devices provide additional communications security between the missile system's control centres and launch facilities.
The systems are part of the ICBM cryptography upgrade (ICU) programme for ICBM missile wings at Air Force bases in Wyoming, Montana and North Dakota.
Boeing has designed, developed and delivered the replacement units and supporting technical data, trainers, support equipment and code processing system modifications.
Boeing Strategic Missile Systems director Peggy Morse said that enabling the air force to install these units is a vital step as they work together to enhance the security of this important nuclear deterrent.
"It's also one of the air force's main requirements for full operational capability of the ICU programme," she said.
Northrop is the prime contractor for the ICU element of the ICBM prime integration contract to sustain and modernise the Minuteman III weapon system, extending its service life.