Department of Defense
DIRECTIVE
NUMBER 5100.20
January 26, 2010
DA&M
SUBJECT: National Security Agency/Central Security Service (NSA/CSS)
References: See Enclosure 1
1. PURPOSE
. Under the authorities vested in the Secretary of Defense by title 10, United States
Code (U.S.C.); title 44, U.S.C.; title 50, U.S.C.; Executive Order (E.O.) 12333; and National
Security Directive 42 (References (a) through (e), respectively) and pursuant to DoD Directives
(DoDDs) 5143.01 and 5144.1 (References (f) and (g)), this Directive reissues DoDD 5100.20
(Reference (h)) to update the mission, organization and management, responsibilities and
functions, relationships, authorities, and administration of NSA/CSS, incorporating and
cancelling DoDD 5100.23 (Reference (i)). This Directive shall be interpreted consistent with
law, policy, and directive, including, as applicable, those related to the Director of National
Intelligence (DNI).
2. APPLICABILITY. This Directive applies to OSD, the Military Departments (including the
Coast Guard at all times, including when it is a Service in the Department of Homeland Security
by agreement with that Department), the Office of the Chairman of the Joint Chiefs of Staff and
the Joint Staff, the Combatant Commands, the Office of the Inspector General of the Department
of Defense, the Defense Agencies, the DoD Field Activities, and all other organizational entities
in the Department of Defense (hereafter referred to collectively as the “DoD Components”).
3. DEFINITIONS
. See Glossary.
4. MISSION
. The National Security Agency (NSA) is the U.S. Government (USG) lead for
cryptology, and its mission encompasses both Signals Intelligence (SIGINT) and Information
Assurance (IA) activities. The Central Security Service (CSS) conducts SIGINT collection,
processing, analysis, production, and dissemination, and other cryptologic operations as assigned
by the Director, NSA/Chief, CSS (DIRNSA/CHCSS). NSA/CSS provides SIGINT and IA
guidance and assistance to the DoD Components, as well as national customers, pursuant to
References (d) and (e). The DIRNSA/CHCSS serves as the principal SIGINT and IA advisor to
the Secretary of Defense, the Under Secretary of Defense for Intelligence (USD(I)), the Assistant
