The National Security Agency (NSA) is a national-level intelligence agency of the United States Department of Defense, under the authority of the Director of National Intelligence. <br /> <br />The NSA is responsible for global monitoring, collection, and processing of information and data for foreign and domestic intelligence and counterintelligence purposes, specializing in a discipline known as signals intelligence (SIGINT). <br /> <br />The NSA is also tasked with the protection of U.S. communications networks and information systems. <br /> <br />The NSA relies on a variety of measures to accomplish its mission, the majority of which are clandestine. <br /> <br />Summary from Wikipedia
