The National Security Agency is responsible for SIGINT.
National Security Agency . The NSA is responsible for global monitoring , collection , and processing of information and data for foreign intelligence and counterintelligence purposes , a discipline known as signals intelligence ( SIGINT ) . Instead , NSA is entrusted with assistance to and coordination of SIGINT elements at other government organizations , which are prevented by law from engaging in such activities without the approval of the NSA via the Defense Secretary .