The Central Security Service (CSS) is an agency of the United States Department of Defense, established in 1972 by a Presidential Directive to promote full partnership between the National Security Agency (NSA) and the Service Cryptologic Elements (SCE) of the United States Armed Forces.
The blue background of the CSS emblem represents "fidelity" and "steadfastness", with the symbols for the cryptologic service elements provided shown clockwise from top right as follows: Army Intelligence and Security Command, United States Marine Corps, Naval Security Group, United States Coast Guard and Air Force Intelligence, Surveillance and Reconnaissance Agency with the symbol of the National Security Agency in the center.
According to the NSA website:
- "By combining NSA and CSS, we are able to provide a more unified Department of Defense (DoD) cryptologic effort. The CSS comprises all U.S. military services—Army, Navy, Air Force, and Marines. To further ensure joint operations, the Director of the NSA is also the Chief of the CSS."
According to James Bamford, NSA/CSS was initially conceived as a separate "fourth service" beside the three U.S. armed services. The latter three resisted this idea, and therefore the CSS was founded as an inter-service organization. The day-to-day work of the CSS is to capture enemy signals (radar, telemetry, radio/satellite communications) using the means of the involved service. For example, the Navy has special submarines for tapping undersea cables; the Air Force operates aircraft with sophisticated antennas and processing gear to listen to enemy radar and radio; and on the ground, the Army operates similar eavesdropping equipment.
The Naval Security Group is a significant addition of signals intelligence and communications security expertise to the organization. Managing the logistics of collection across the globe and securing the systems used inside the agency and other branches of the military are particularly useful contributions from the Naval Security Group. The Computer Network Defense Red Team run by the Navy at the Fleet Information Warfare Center also operates directly under the Naval Security Group and provides critical operational and exercise support to commands to improve their ability to fend off malicious computer activity. Red Team refers to a group of subject-matter experts tasked with playing the role of the enemy in training exercises, often referred to as peer review or penetration testing in private industry. ("Red" is associated with secure communications, as opposed to "black" unsecured communications.)