The
National Security Agency (
NSA) is an
intelligence organization of the United States government, responsible for global monitoring, collection, and processing of information and data for foreign intelligence and
counterintelligence purposes – a discipline known as
signals intelligence (SIGINT). NSA is concurrently charged with
protection of U.S. government communications and information systems against penetration and network warfare. Although many of NSA's programs rely on "passive" electronic collection, the agency is authorized to accomplish its mission through active
clandestine means, among which are physically
bugging electronic systems and allegedly engaging in
sabotage through
subversive software. Moreover, NSA maintains physical presence in a large number of countries across the globe, where its
Special Collection Service (SCS) inserts eavesdropping devices in difficult-to-reach places. SCS collection tactics allegedly encompass "close surveillance, burglary, wiretapping, breaking and entering".