(CSS) Central Security Service

The Central Security Service (CSS) is a joint military and intelligence organization of the United States Department of Defense. It was established in 1972 to promote cooperation and coordination between the U.S. military's signals intelligence (SIGINT) components, such as the National Security Agency (NSA), and the U.S. military's information assurance components. The CSS works closely with the NSA to provide secure communications and to improve the sharing of signals intelligence information between the military and the intelligence community. The CSS also provides support to military operations through the collection and analysis of signals intelligence and the protection of military communications networks and systems.

https://en.wikipedia.org/wiki/Central_Security_Service