Title: Classification Guide for SIGINT Material Dating from 16 August 1945 – 31 December 1967

Release Date: 2014-06-18

Document Date: 2011-11-21

Description: This NSA classification guide, dated 21 November 2011, covers signals intelligence material that as to be kept secret for more than the standard 60 years: see the Der Spiegel article The NSA in Germany: Snowden’s Documents Available for Download, 18 June 2014.

Document: TOP SECRET//SjyTK//NOFÜRN

NATIONAL SECURITY AGENCY
CENTRAL SECURITY SERVICE

(U) CLASSIFICATION GUIDE FOR
SIGINT Material Dating from 16 August 1945 *31 December 1967

Effects Dale: 21 December 201 ]

Revised Dateis): 24 February 2012,13AprlI 2012
25 April 2012

CLASSIFIED BY
I nl id licence Director

REASON FOR CLASSIFICATION:

E4(c), 1.4 (ti)

DECLASSIFY ON: *75 years from da le of
nulle rial or event, as Indicated

ENDORSED HY:|

De I inly Associate Director for Policy and
Records

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(U) Change Register

Change No. Change Date Made mm/dd/yy By (initials)
1 Numerous administrative changes were made to clarify certain guidance, correct some errors in dates, revise the proposed exemption categories, and correct typos. 02/24/12 SLS
2 Entry 24 was amended to account for two specific exceptions. 4/13/12 SLS
3 Entry 3 was amended to bring it in line with previous guidance regarding intercept or reference to specific intercept of belligerent or non-belligerent communications through 31 December 1946 4/25/12 SLS



























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(U) Classification Guide for SIGINT Material Dating Prior to i January 1968

(U) PUBLICATION DATE:

(U) OFFICE OF ORIGIN: SJD
(U//KOUO) POC; S02

(U) PHONE:

(U) ORIGINAL CLASSIFICATION AUTHORITY:
SIGINT Director,

(U) This classification guide describes the SIGINT material that is dated from 16 August
1945 - 31 December 1967 and warrants protection for more than 50 years. It supersedes
all prior guidance relating to material originating during this timeframe. This guidance
pertains to NSA/CSS as urcll as to its predecessor organizations.

Description of Information C Jussi fica Lion/Ma rk i ni> s Reason Declass Remarks

1. (U) All sources- and methods- related metadata added to SIGINT product reports by NSACKS or included in NS ACSS metrics reports CONFIDENT! AU/RE L TO USA FVEY at a minimum 50X1 50X3 50X6 *75 years from date of material (U//FOUO) This includes information such as SIGINT addresses (SlGADs), Producer Designator Digraphs (PDDGs), Case Notations {CASNs), RASLX Manual designators, intercept designators, Skis, Crypt System Titles, Intel 1 igenee Source Indicators (iSLs), 'lime of Intercept (TOl), Communications Lanes (foreign F ROM/TO enti t ies), Message Telex numbers assigned by foreign target, number of messages collected for a specific target, number of messages decrypted for a specific target, etc. (U) Exceptions: For the period of the V ictnam conflict (through 31 December 1967) - all metadata for otherwise releasable reports in which the targeted entity was a participant in the Vietnam conflict Ls UNCLASSIFIED. (U//POUO) The methodologies used by

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NSA/CSS to log, track, account for, and analyze collection prior to 1968 are still used today. Revealing this “who,” “when,” “where,” and “how” could provide an adversary with a great deal of insight into NSA’s targets, collection sites, and other collection- and analysis- related information that is still being used today. (U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
2. (S//NF) Information revealing SECRET//REL TO USA, 75X1 *75 years (U) The fact of NSA/CSS
the fact of NSA/CSS targeting, FVEY at a minimum 75X3 from either targeting, collecting, or
collecting, or processing the 75X6 the date of processing against any nation
communications of these material or not listed as classified
specific foreign the end of through 1967 is
countries/international the UNCLASSIFIED.
organizations: particular
partnership, (U) Revealing these specific
- Algeria after 31 Dec 1946 whichever targets will enable
- Belgium after 31 Dec 1946 is longer adversaries to deduce the
- France after 31 Dec 1946 strength and range of
- Germany (i.e., West Germany) NSA/CSS’s capabilities at
after 31 Dec 1946 that time. When there is
- Netherlands after 31 Dec 1946 direct link between the
- Norway after 31 Dec 1946 communications systems used
- Saudi Arabia after 31 Dec then and those used today,
1946 the targets can adopt blanket
- Sweden after 31 Dec 1946 denial practices not currently
- Tunisia after 31 Dec 1946 used because they simply do
- Turkey after 31 Dec 1946 not appreciate how well their
signals are currently being
- Taiwan (Formosa) after exploited by NSA/CSS. In
31 Dec 1949 addition, certain historical
targets are also (and were in
- Italy after 31 Dec 1947 the timeframe covered by this
- Jordan after 31 Dec 1947 guide) SIGINT partners, and
revealing that NSA/CSS
- Denmark after 31 Dec 1953 targeted nations that are
- South Korea after 31 Dec current partners could have
1953 an immediate negative effect
on those relationships.
- Japan after 31 Dec 1954
(U) The fact that NSA/CSS
- Austria after 31 Dec 1955 processed intercepted Israeli
communications during the
- Israel for any timeframe (see USS Liberty incident (24

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remark for specific exception) - Pakistan for any timeframe - Singapore for any timeframe - all international organizations May - 8 June 1967) is UNCLASSIFIED. (U) Serious or exceptionally grave damage to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
3. (S//NF) Information revealing SECRET//NOFORN 75X1 *75 years (S//NF) Second Party
the fact of NSA/CSS targeting, 75X3 from either partnerships are among
collecting, or processing the 75X6 the date of NSA/CSS’s strongest, oldest,
communications of a Second Party country 75X9 material or the end of the partnership, whichever is longer and most important. Revealing the fact that NSA/CSS targeted their communications at any time would most likely have serious implications for, and could cause irreparable damage to, the partnerships. (U) Serious damage to national security can be expected if this material were to be declassified.
4. (U) The identities of specific SECRET//REL TO USA, 75X1 *75 years (U//FOUO) NSA/CSS’s
NSA/CSS Third Party SIGINT FVEY at a minimum 75X3 from either Third Party partners provide
partners 75X6 the date of material or the end of the particular partnership, whichever is longer NSA with unique and valuable insights on counterterrorism, combating proliferation, and regional stability issues. They also often provide NSA/CSS information about each other. Although they may suspect they were targets prior to 1968, their level of cooperation with NSA is expected to diminish if it became a known fact. Conversely, if information that NSA/CSS has relating to these countries that is outside the scope of the partnerships were to be released, the countries could gain insight into NSA’s other SIGINT capabilities, and could also become aware of information that NSA/CSS has not been sharing. The future of NSA/CSS’s Third Party SIGINT foreign partnerships would be at stake.

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(U) Serious or exceptionally grave damage to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
5. (U) The fact that NSA/CSS CONFIDENTIAL//REL TO 75X1 *75 years (U//FOUO) NSA/CSS’s
shared particular SIGINT USA, FVEY at a minimum 75X3 from either Second Party partnerships are
material with a specific Second 75X6 the date of extraordinarily close, and in
Party partner, when the partner is identifiable 75X9 material or the end of the particular partnership, whichever is longer some cases it is impossible to tell where one partner’s work ends and another’s starts. In many cases, for a variety of reasons originating within the respective partner’s government, Second Party partners insist that their involvement in specific projects or operations must not be released. The UKUSA agreement, signed in 1946, mandates that the Second Parties respect each others’ preferences in these cases. (U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
6. (U) The fact that NSA/CSS SECRET//REL TO USA, 75X1 *75 years (U//FOUO) NSA/CSS’s
shared particular SIGINT FVEY at a minimum 75X3 from either Third Party partners provide
material with a specific Third Party partner, when the partner is identifiable 75X6 the date of material or the end of the particular partnership, whichever is longer NSA with unique and valuable insights on counterterrorism, combating proliferation, and regional stability issues. If it were revealed that NSA/CSS shared particular information with specific Third Party partners (essentially revealing the countries with which it had Third Party SIGINT partnerships prior to 1968), the future of its Third Party SIGINT foreign partnerships would be at stake. (U) Serious or exceptionally grave damage to national security can be expected if

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this material were to be declassified, depending on the particular information being revealed.
7. (U) Information revealing SECRET//REL TO USA, 50X1 *75 years (U) Exceptions:
NSA/CSS targeting, collecting, FVEY at a minimum 50X3 from date
or processing diplomatic or leadership communications of a specific foreign country/countries, international organization, group of individuals, or individual (post 31 December 1946) 50X7 of material - (U) diplomatic/leadership communications collected during and related to the Cuban Missile Crisis (1 January 1959-31 December 1963) are UNCLASSIFIED - (U) North Vietnamese, Laotian, or Cambodian diplomatic/leadership communications related to the Vietnam conflict and collected between 1 January 1960 and 31 December 1975 are UNCLASSIFIED (U//FOUO) Indicating whose diplomatic/leadership communications NSA/CSS targeted, collected, and/or processed prior to 1968 would cause diplomatic challenges for the U.S., and could also enable a targeted country that is still using similar communications systems to change their systems, thereby denying NSA/CSS valuable intelligence. (U) Serious or exceptionally grave damage to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
8. (U//FOUO) Information SECRET//REL TO USA, 50X1 *75 years (U//FOUO) Indicating whose
revealing NSA/CSS targeting, collecting, or processing of specific international commercial (ILC) communications (post 31 December 1946) FVEY at a minimum 50X3 from date of material ILC communications NSA/CSS targeted, collected, and/or processed prior to 1968 could also enable a target that is still using similar communications systems to change its systems, thereby denying NSA/CSS valuable intelligence.

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(U) Serious or exceptionally grave damage to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
9. (U) Information that contains or CONFIDENTIAL//REL TO 75X1 *75 years (U//FOUO) This includes the
reveals foreign SIGINT partner USA, FVEY at a minimum 75X3 from either basic “fact of’ specific Third
equities 75X6 the date of Party partnerships, names of
75X9 material or personnel associated with
the end of partner organizations (Second
the or Third Party), indications of
particular projects that were worked
partnership, with specific foreign partners
whichever (Second or Third Party),
is longer collection locations in partner nations (Second or Third Party), etc.
(U//FOUO) NSA/CSS’s foreign partners provide NSA with unique and valuable insights on a wide variety of issues that are critical to U.S. national security (e.g., counterterrorism, combating proliferation, and regional stability). It is a given that they need to protect their equities as vehemently as NSA/CSS protects its own. If NSA/CSS were to release information that revealed the equities of its foreign partners (Second as well as Third Parties), the future of its SIGINT foreign partnerships would be at stake.
(U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
10. (U//FOUO) Information CONFIDENTIAL//REL TO 75X1 *75 years (U//FOUO) Revealing
revealing specific overseas USA, FVEY at a minimum 75X3 from either specific overseas collection
collection and High-Frequency 75X6 the date of and HFDF locations could
Direction Finding (HFDF) material or adversely affect Third Party
locations that remain open closure of SIGINT partnerships and
today site, reveal NSA/CSS’s HFDF
whichever capability strengths and
is longer weaknesses. Such revelations

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would identify NSA/CSS’s Third Party partners and enable its adversaries to develop countermeasures against its strengths and exploit its weaknesses. (U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
11. (S//SI//REL TO USA, FVEY) SECRET//SI//REL TO USA, 75X1 *75 years (S//SI//REL TO USA,
The fact that NSA/CSS FVEY 75X3 from either FVEY) Revealing the fact
conducted/conducts covert 75X6 the date of that NSA/CSS conducted
SIGINT operations at unspecified officially flagged U.S. facilities abroad 75X7 material or end of overall activity, whichever is longer covert SIGINT operations from officially flagged U.S. facilities abroad would impair the effectiveness of intelligence methods currently in use; would reveal information that would cause serious harm to relations between the United States and a foreign government, or to ongoing diplomatic activities of the United States; and could impair the ability to provide protection services to those U.S. Government officials authorized protection (e.g., President, Vice President).
12. (S//REL TO USA, FVEY) The TOP SECRET//SI//REL TO 75X1 *75 years (S//SI//REL TO USA,
association of a specific USA, FVEY 75X3 from either FVEY) Revealing that
location with an SCS site, the 75X6 the date of NSA/CSS conducted covert
existence of which is releasable to Second Party partners 75X7 material or end of overall activity, whichever is longer SIGINT operations from specific officially flagged U.S. facilities abroad would impair the effectiveness of intelligence methods currently in use; would reveal information that would cause serious harm to relations between the U.S. and a foreign government, or to ongoing diplomatic activities of the U.S.; and could impair the ability to provide protection services to those U.S. Government officials authorized protection (e.g., President, Vice President).

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(U) Exceptionally grave damage to national security can be expected if this material were to be declassified.
13. (S//REL TO USA, FVEY) The TOP SECRET//SI//NOFORN 75X1 *75 years (S//SI//REL TO USA,
association of a specific 75X3 from either FVEY) Revealing that
location with an SCS site that is 75X6 the date of NSA/CSS conducted covert
NOFORN 75X7 material or SIGINT operations from
end of specific officially flagged
overall U.S. facilities abroad would
activity, immediately impair the
whichever effectiveness of intelligence
is longer methods currently in use; would reveal information that would cause serious harm to relations between the United States and a foreign government, or to ongoing diplomatic activities of the United States; and could impair the ability to provide protection services to those U.S. Government officials authorized protection (e.g., President, Vice President).
(U) Exceptionally grave damage to national security can be expected if this material were to be declassified.
14. (U) Information revealing CONFIDENTIAL//REL TO 50X1 *75 years (U//FOUO) NSA/CSS uses
specific sources and methods USA, FVEY at a minimum 50X3 from date the same sources and
used by NSA/CSS to target, 50X6 of material methods to obtain SIGINT
collect, and/or process SIGINT today as it did prior to 1968.
and that are currently used Revealing the specific
today sources and methods used by NSA/CSS to target, collect, and/or process SIGINT would enable targets to adopt blanket denial practices not used today because they simply do not appreciate how well their signals are currently being exploited by NSA/CSS.
(U) See Entry 31 for additional information.
15. (TS//SI//REL TO USA, FVEY) TOP SECRET//SI//NOFORN 50X1 *75 years (TS//SI//REL TO USA,
Information revealing the fact 50X3 from date FVEY) NSA/CSS’s covert
of, as well as details relating to, 50X6 of material SIGINT activities, such as
NSA/CSS conducting covert SIGINT enabling and the use

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SIGINT activities, including of particular cover
material dealing with SIGINT mechanisms, are much the
enabling; cover plans, same today as they were prior
programs, and mechanisms; to 1968. Revealing the
and/or clandestine SIGINT specific covert activities would nullify the particular programs where they are successfully used today. Targets would adopt blanket denial practices not used today because they simply do not appreciate how NSA/CSS’s covert activities support SIGINT successes.
(U) Exceptionally grave damage to national security can be expected if this material were to be declassified.
16. (U) TICOMdocuments dated CONFIDENTIAL//REL TO 50X1 *75 years (U) TICOM documents
prior to 31 December 1967 USA, FVEY at a minimum 50X3 from date should only be released if
where the acquired document 50X6 of material they would have been
was originally created by the 50X9 released by the U.S. or
U.S. or a Second Party partner and was in the possession of an Second Party directly.
"enemy" organization. (U) TICOM documents that may be declassified and released include acquired code books and the description of applications of techniques to cryptographic systems.
(U//FOUO) TICOM was a joint Five Eyes effort. NSA/CSS’s Second Party partnerships are extraordinarily close, and in some cases it is impossible to tell where one partner’s work ends and another’s starts. In many cases, for a variety of reasons originating within the respective partner’s government, Second Party partners insist that their involvement in specific projects or operations must not be released. The UKUSA agreement mandates that the Second Parties respect each others’ preferences in these cases.

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(U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
17. (U) TICOMinterrogation CONFIDENTIAL//REL TO 50X1 *75 years (U) TICOM documents
reports USA, FVEY, at a minimum 50X3 from date should only be released if
50X6 of material they would have been
50X9 released by the U.S. or Second Party directly.
(U) In some cases, TICOM interrogation reports remain not releasable due to BRUSA
agreements to protect personal information whose release could reasonably be expected to constitute an unwarranted invasion of personal privacy of a living person.
(U//FOUO) TICOM was a joint Five Eyes effort. NSA/CSS’s Second Party partnerships are extraordinarily close, and in some cases it is impossible to tell where one partner’s work ends and another’s starts. In many cases, for a variety of reasons originating within the respective partner’s government, Second Party partners insist that their involvement in specific projects or operations must not be released. The UKUSA agreement mandates that the Second Parties respect each others’ preferences in these cases.
(U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
18. (U) ELINT material related to S//REL TO USA, FVEY at a 50X1 *75 years (U//FOUO) Many of the
radar/weapons systems that are minimum 50X3 from date collection and exploitation
still used today of material methods used prior to 1968 continue to be employed in the Intelligence Community.

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Declassifying ELINT material that is 50 years old (and older) would enable adversaries, who do not appreciate how well their signals are currently being exploited by NSA, to ascertain those collection and analysis techniques and subsequently adopt denial practices that could preclude further intelligence exploitation. Such denial would hamper intelligence of the modification of old systems as well as the newest ones. (U) Serious or exceptionally grave damage to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
19. (U//FOUO) A single ELNOT or list of ELNOTs or designators that equate to specific radars, including those from weapons systems, or similar non- communications signal devices weapons system when associated with amplifying data that identifies the emitter radar, weapon system, country of origin, or ELINT signal acquisition method. CONFIDENTIAL//REL TO USA, FVEY at a minimum 50X1 50X3 *75 years from date of material (U//FOUO) This category includes information equating a specific ELNOT with a specific radar nickname, such as a NATO nickname, or a radar model number. (U//FOUO) A single ELNOT or list of ELNOTs or designators, e.g., B329A, 1222Z, T6090, 123MZ, when used without amplifying data that identifies the emitter radar, weapon system, or country of origin, or ELINT signal acquisition method is UNCLASSIFIED (C//REL TO USA, FVEY) Examples: - the fact that P307Z and P334A emanate from the Crotale surface-to-air missile is classified CONFIDENTIAL//REL TO USA, AUS, CAN, GBR, NZL - the fact that A427B emanates from SLOT BACK radar is

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CONFIDENTTAL//REL TO USA, AUS,CAN,CiBK, NZL (U//KOUO) Many of the eolleetion and exploitation methods used prior to l%fi eontinue to be employed today. Declassifying LL1NT material that Is 50 years old (and older) would enable adversaries, who do not appreeiaie how well their signals ate eurrently being exploited by NS A, io aseertain those eolleetion and analysis [ethniques and subsequently adopt denial praetiees that eould preelude further intelligente exploitation. Sueh denial would hamper mtellienee of the modifieation of old systems as well as the newest ones. (U) Various levels of harm to national seeurity ean be expeeied if this material were to be declassified, depending on the partieular information being revealed.
20. (U//KOUÜ) FISINT-rcLited material (i.e., information related to eolleetion, processing, and analysis of telemetry and beacons, command uplinks, video daia links, tracking, and arming/fusing/eommand signals as well as reporting based on said data types) 3ECRET//REL TO USA, FVEY ata minimum 50X1 50X3 *75 years from date of material (U) Exceptions: - Refer to the following Information Management Ins truetions ( l M1 s) for guidante on spécifié UNCLASSIFIED FISINT- relaied information: - DEES MAC 1M1 - Soviet Deep Space Telemetry Collection 1M1 ■ (U//EOUO) FISINT activity began in 1056, and amounts to information that weapons designers use to verify weapon system performance capabilities. The exact

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collection and exploitation methods used from that time are still being used successfully today. (U//FOUO) Declassification of FISINT-related material that is 50 years old and older would show NSA/CSS’s ability to fully exploit the data, even with the lack of an identification key and poor signal quality, and likely lead to widespread data denial practices among target countries who do not currently appreciate how well their signals are currently being exploited by NSA. This would deprive the U. S. of vital knowledge of foreign weapons and space systems, which in turn would ultimately lead to policy decisions being made on faulty/incomplete data and to increased loss of life and mission failure during future military operation. (U) Serious or exceptionally grave damage to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
21. (U//FOUO) SIGINT material TOP SECRET//SI//NOFORN 50X1 *75 years (C//REL TO USA, FVEY)
pertaining to counterespionage 50X3 from date Foreign intelligence services’
efforts that reveal NSA/CSS knowledge, exploitation, and analysis of adversaries’ tradecraft that is still being used today 50X6 of material tradecraft is unique to the individual service. Declassifying information indicating that NSA/CSS has successfully exploited their activities, or that it understands their methodologies, would enable the adversaries to refine or alter their practices to the point where it might be denied the information/access entirely (an example would be cover names of agents of an adversary’s intelligence service). Adversaries’

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underlying tradeerail
(ine I udi ng com mun ieat ions
methods and patterns, and all
aspects of recruitment and
handling ofa^ents) generally
remains the same over time,
and must he protected in
order to maintain NSA/CSS's
ability to exploit it. In
addition, such material may
reveal the identities of a
person, or the eooperation of
a still-Iivmg person, who was
the source of information for
evidence that was compiled
against spies who were Liter
arrested, causing that
person’s life to be in
jeopardy.

(U) Exceptionally grave
damage to national security
can be expected if this
material were to be
declassified.

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(C.vRhL IT) USA, PVliY) Releasing deerypts allows the targit to deduee the strength and range of NSA/CSS’s eapabilities at that time. When there is direet link between the eryptologies used then and those used today, a straightforward interpolation would allow the target who builds and uses indigenous logics to determine the minimum strength required to defeat NSA/CSS’s diagnosis and exploitation today. They ean then build and deploy strongir logies or design and deploy logies using different erypto-prineiples than those used previously. When eommereially available logies were used, the target ean buy strongir logies or purehase from a different supplier, again with strength and erypto design prineiples to defeat NisA/CisS's exploitation. When N is A/CS is release s a se lee ted targes deerypts, it has already seen substantive ehanges in that target's use of eryptograph.y.
25. (U) SIGINT serialized Produet Reports that eon lain cryptologic information CON HDH N ] 1A17/SI//REL TO USA, FVEY ai a minimum 50X1 50X3 50X6 *75 years from date of material

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(UJ Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
26. (Ul SIGENT serialized Product CONF IDENTIAL7S L7RLL TO 50X1 *75 years (SWSI//REL TO USA,
Reports consisting of or USA, FVEY at a minimum 50X3 from date FVEY) SIG1NT serialized
containing decrypt for the Soviet Bloc or People's Republic of China for the period 1 January 19? 1 through 31 December 1967 50X6 of material product reports for the Soviet Bloc or People’s Republic of China eons Ls ting of or containing decrypts for the period 16 August 1945 through 31 December 1950 are UNCLASSIFIED, as long as all relevant sources - and me [hods-related metadata has been redacted. (U//FOUO) Relevant sources- and methods-relaied metadata includes post- BRUSA system titleS, which did not exist until 1946 and eompnsed aeombmationof four or more letters and/or numbers. In addition, it includes ease notations, RASIN Manual designators, and intercept designators, which are not strictly erypianalytie, but have relevance to erypianalytie equities. (U) Information reveal i ng NSA/CSS targeting, collecting, or processing of diplomatic or leadership communications of a specific foreign country /countries, international organization, group of individuals, or individual - for any timeframe - remain classified, except for those decrypted using techniques declassified in the versions of Milnanv Crvotanalviies 1 and

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released by NSA, that were collected during and related to the Cuban Missile Crisis (1 January 1959-31 December 1963), and North Vietnamese, Laotian, or Cambodian diplomatic/leadership communications collected prior to 31 December 1975, which are UNCLASSIFIED. (C//REL TO USA, FVEY) Releasing decrypts allows the target to deduce the strength and range of NSA/CSS’s capabilities at that time. When there is direct link between the cryptologics used then and those used today, a straightforward interpolation would allow the target who builds and uses indigenous logics to determine the minimum strength required to defeat NSA/CSS’s diagnosis and exploitation today. They can then build and deploy stronger logics or design and deploy logics using different crypto-principles than those used previously. When commercially available logics were used, the target can buy stronger logics or purchase from a different supplier, again with strength and crypto design principles to defeat NSA/CSS’s exploitation. (U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
27. (U) SIGINT serialized Product CONFIDENTIAL//SI//REL TO 50X1 *75 years (S//SI//REL TO USA,
Reports consisting of or containing decrypts for North Korea for the period 1 July 1951 through 31 December 1967 USA, FVEY at a minimum 50X3 50X6 from date of material FVEY) SIGINT serialized product reports for North Korea consisting of or containing decrypts for the period 16 August 1945

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through 30 June 10? 1 arc
UNCLASSIFIED, as long as
all relevant metadata,
including sources - and
me [hods -related information,
has been redacted.

(U/'FOUO) Relevant
sources- and methods-related
metadata includes post-
BRUSA system titles, which
did not exist until 1046 and
comprise a combination of
four or more letters and/or
numbers. In addition, it
includes ease notations,
RASIIV Manual designators,
and intercept designators,
which are not strictly
erypianalytie, but have
relevance to erypianalytie
equities.

(U) All reports by Korea-
based field units based on the
exploitation of manual codes
and e iphers, provided they
make no connection to
encrypted communieaiions,
during and re lined to the
Korean War, 2? June 19?0 -
31 December 19? 3 are
UNCLASSIFIED.

(U) Information revealing
NSA/CSS targeting,
collecting, or processing of
diplomatic or leadership
communications of a specific
foreign country/countries,
international organization,
gn)up of individuals, or
individual - lor any
timeframe - remain
classified, except for those
decrypted using techniques
declassified in the versions of
Military Cryplnnulylics 1 and
11, written b1

|and officially
released by MSA that were

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collected during and related
to the Cuban Missile Crisis (1
January 1959-31 December
1963), and North
Vietnamese, Laotian, or
Cambodian
diplomatic/leadership
communications collected
prior to 31 December 1975,
which are UNCLASSIFIED.

(C//REL TO USA, FVEY)
Releasing decrypts allows the
target to deduce the strength
and range of NSA/CSS’s
capabilities at that time.

When there is direct link
between the cryptologics
used then and those used
today, a straightforward
interpolation would allow the
target who builds and uses
indigenous logics to
determine the minimum
strength required to defeat
NSA/CSS’s diagnosis and
exploitation today. They can
then build and deploy
stronger logics or design and
deploy logics using different
crypto-principles than those
used previously. When
commercially available logics
were used, the target can buy
stronger logics or purchase
from a different supplier,
again with strength and
crypto design principles to
defeat NSA/CSS’s
exploitation.

28. (U) SIGINT serialized Product CONFIDENTIAL//SI//REL TO
Reports consisting of or USA, FVEY at a minimum

containing decrypts for any
other target (i.e., not Soviet
Bloc or People’s Republic of
China from 1 Jan 1951-31 Dec
1967, not North Korea from 1
July 1951-31 Dec 1967) for the

50X1

50X3

50X6

*75 years
from date
of material

(U) Various levels of harm to
national security can be
expected if this material were
to be declassified, depending
on the particular information

being revealed.________________

(U) Information revealing
NSA/CSS targeting,
collecting, or processing of
diplomatic or leadership
communications of a specific
foreign country/countries,
international organization,
group of individuals, or

TOP SECRET//SI/TK//NOFORN

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target’s decrypts, it has already seen substantive changes in that target’s use of cryptography. (U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
29. (U) Alphabet Generators'. CONFIDENTIAL//SI//REL TO 50X1 *75 years (U) A document that
Documents that demonstrate or USA, FVEY at a minimum 50X3 from date demonstrates or includes the
include the application of any cryptanalytic technique relating to Alphabet Generator systems that became operational after 15 August 1945 50X6 of material application of any cryptanalytic technique to an electromechanical cipher system that is an alphabet generator is UNCLASSIFIED only if the system is UNCLASSIFIED in accordance with the WWII Guidance. (U) This guidance pertains to documents relating to: • Wired wheels (such as ENIGMA), • Telephone selectors (such as PURPLE, RED, JADE, and CORAL), and Hagelin alphabet generators. (C//REL TO USA, FVEY) In this time frame, commercial companies and nation states developed and deployed cryptographies which have many features still in use in cryptosystems NSA/CSS exploits today. Documents that detail the application of cryptanalytic techniques to these earlier systems will reveal capabilities still in use today against operational target cipher systems. (U) Various levels of harm to national security can be expected if this material were

TOP SECRET//SI/TK//NOFORN

FOP SE C RET//S1/TK//N OFORN

to he deelassiiied, depending on the panieular information being revealed.
30. (U) Cryptosy stem s Ot be r Than Alphabet Generators: Doeuments that demonstrate or inelude the appheation of a eryptanalytie teehniqne to any eipher system other than an alphabet generator CON P ] Dlf NT] A L'7S ]//KliL TO USA, FVEY at a minimum 50X1 50X3 50X6 *75 years from date of material (U) This gnidanee ineludes doeuments relating to any eleetromeehanieal systems that are key generators, to inelude Hagelin key generators and TUNNY. (U) LseepLion: When a doeument only eontains speeifie previously deelassiiied teehniqnes applied to a low-grade or medium-grade ery ptograph ie system, the doeument will he UNCLASSIFIED unless il deals with the applieationof depth reading Or depth- reading teehniqnes. Previously dee lassiTied teehniquesare those deelassiiied in the versions of Military Crvntanalvties 1 and 11. i .tun lv-. ^^^^^fotfieially released by NS A. (U) Cryptanaiytic worksheets remain elassified if they: - are for key generators, and/or - i ndie ate depth or depth - reading teehniqnes (e.g., have different eipher textsassoeiated with the same key) areassoeiatedwitha spee ifie operat lonal target (O/KLL TO USA FVEY) In this time frame, eommereial eompames and nation states developed and deployed eryptographies whieh have many features

FOP SE C RET//S1/TK//N OFORN

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still in use in cryptosystems
NSA/CSS exploits today.
Documents that detail the
application of cryptanalytic
techniques to these earlier
systems will reveal
capabilities still in use today
against operational target
cipher systems.

31. (TS//SI//REL TO USA, FVEY)
Commercial Cryptanalytic
Relationships: Documents that
contain information that implies
that commercial companies
cooperate with NSA/CSS or
Second Party partners to render
their products exploitable from
a cryptanalytic standpoint

TOP SECRET//SI//REL TO
USA, FVEY

75X1

75X3

75X6

75X9

*75 years
from either
the date of
material or
end of the
relation-
ship,

whichever
is longer

(U) Various levels of harm to
national security can be
expected if this material were
to be declassified, depending
on the particular information

being revealed._______________

(U) Such documents may also
be compartmented.

(TS//SI//REL TO USA,
FVEY) Exposure of any
company’s commercial
cryptanalytic relationship
with NSA/CSS, even for a
company no longer in
existence, will damage
NSA/CSS’s credibility with
current companies who are
approached for assistance.
Exposure of even decades-
old commercial cryptanalytic
relationships may cause
significant harm to the
company’s reputation and
financial status.

32. (C//REL TO USA, FVEY)
Commercial Information
Security Devices: Documents
containing details of
commercially available
cryptographic algorithms,
information security devices, or
systems that identify an actual
vulnerability not currently
publicly known, or details
relating to NSA/CSS
exploitation of a publicly
known vulnerability

CONFIDENTIAL//SI//REL TO 50X1
USA, FVEY at a minimum 50X3

50X6

*75 years
from date
of material

(U) Exceptionally grave
damage to national security
can be expected if this
material were to be
declassified._________________

(C//REL TO USA, FVEY)
Disclosing details of
vulnerabilities or NSA/CSS’s
methods of choice for
exploitation will allow
commercial companies to fix
those weaknesses in existing
systems and avoid
implementing them in future
systems. Frequently,
commercial companies make
the same or similar mistakes
through several generations
of their products.

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(U) Information Security Devices provided to other countries by the U.S. Government are considered Commercial Information Security Devices. (U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
33. (U) Indigenous Information CONFIDENTIAL//SI//REL TO 50X1 *75 years (C//REL TO USA, FVEY)
Security Devices: Documents containing details of indigenous cryptographic algorithms, information security devices or systems USA, FVEY at a minimum 50X3 50X6 from date of material For indigenous security devices or systems, any documents revealing NSA/CSS’s knowledge of the cryptography of those devices will risk its ability to diagnose and exploit these devices, and in some cases, knowledge it received from sensitive HUMINT sources. (U) Various levels of harm to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
34. (U//FOUO) Signal designators CONFIDENTIAL//SI//REL TO 50X1 *75 years (U//FOUO) Examples of
when combined with any details that would reveal a target user/country or when associated with cryptanalytically relevant information, such as UKUSA nicknames, coverterms, or any targeting, collection, or exploitation details USA, FVEY at a minimum 50X3 50X6 from date of material signal designators include RASIN Manual designators and TEXSIGs. (U//FOUO) Signal designators with no indication of target user or country are UNCLASSIFIED. (U) This information is directly linked to NSA/CSS sources and methods for collection and processing. The Second Party standards and notation developed under UKUSA are still in use today. (U) Various levels of harm to national security can be expected if this material were to be declassified, depending

TOP SECRET//SI/TK//NOFORN

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35. (U//FOUO) Documents dated
after December 3 ], 1956 [hat
demonstrate or include the
application of a signals analytic
technique to any digital or
digitized system

36. (S//REL TO USA, FVEY)
Information identifying specifie
organizations or government
agencies ihai faeiliiaied
NS A/CSS close access
Operations

CON FIDE NTl ALV/SI//REL TO
USA, FVEY at a minimum

SECRET// REL TO USA,
FVEY

50X1

50X3

50X6

50X1

50X3

*75 years
from daie
of material

*75 years
from daie
of material

on the particular information
being revealed.

(U) These organizations may
be U.S. companies, specific
units within a U.S.
government agency, U .S.
national laboratories, or U.S.
academic institutions.

(S//REL TO USA, FVEY)
Revealing the organizations
[hat facilitated close access
operations would have a high
probability of causing harm
to current operations in which
those organ izat ions eon ti n ue
to have a role or had a role in
the past (even if the
organization is now defunct).

(U) Serious damage to
national security can be
expected if this material were
to be declassified.

3 7. (S//RE L L O U S A, F V HY) L he
fact that NS A/CSS has
successfully conducted and has
an organization devoted to
close access operations

SECRET// REL TO USA,
FVEY

50X3

*75 years
from daie
of material

(S//REL TO USA, FVEY)
The exact col lee tion and
exploitation methods used
prior to l96fi are still being
used successfully today.
Declassifying close access

TOP SECRET//SI/TK//NOFORN

TOP SEC RET//S1 /TKJ/N OFORJN

material that is 50 years old
{and older) will enable tarots
to adopt blanker denial
praetiees not used today
beeause they simply do not
appreeiare how well their
signals are eurrently being
exploited by NS AC Sis.

(U) Serious damage to
national seeurity ean be
ex pee red if this material were
ro be declassified.

TOP SEC RET//S1/TK//N OFORJN

TOP SECRET//SI/TK//NOFORN

magnetometers, accelerometers, and commercial microphones. This includes information dealing with receivers and the use of radar systems against mechanical or electromechanical office equipment, as well as tools/techniques no longer being used (such as magnetometers, accelerometers, audio signals, power and/or signal line clamps) and that have little chance of future use. (S//REL TO USA, FVEY) Indications that NSA has knowledge of specific and/or unusual parameters, or of NSA’s capabilities, could provide information that could be used to understand and counter the collection capability. (U) Serious or exceptionally grave damage to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
39. (S//REL TO USA, FVEY) Information describing concealment /camouflage techniques for sensors/systems used inNSA/CSS close access operations SECRET//SI// REL TO USA, FVEY at a minimum 50X3 50X6 *75 years from date of material (U) While removal of such sensors/systems is desired once a facility is no longer of interest, is not always feasible. Inadvertent discovery of such systems/sensors could jeopardize future operations and/or raise questions about or point to NSA’s involvement. (U) Serious or exceptionally grave damage to national security can be expected if this material were to be declassified, depending on the particular information being revealed.
40. (S//REL TO USA, FVEY) Information that identifies a TOP SECRET//SI// REL TO USA, FVEY at a minimum 50X3 50X6 *75 years from date (S//REL TO USA, FVEY) Covert or clandestine

TOP SECRET//SI/TK//NOFORN

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specific target, contains details or parameters relating to specific targets, and/or contains details that could possibly identify a covert or clandestine listening post used by NSA/CSS of material Listening Posts (LPs) are physical locations that are close to the target facility and serve as a collection point for the signals of interest. Identification of a LP could result in the identification of information such as the identities of cooperating parties/people. Exposure of such information could adversely impact current and future operations by revealing information about partner relationships. (U) Exceptionally grave damage to national security can be expected if this material were to be declassified.
41. (S//SI//REL TO USA, FVEY) Details, including the “fact of,” regarding NSA/CSS collection capability against Short Duration Signals (SDS) SECRET//SI//REL TO USA, FVEY 50X3 50X6 *75 years from date of material (S//SI//REL TO USA, FVEY) The methods used to exploit SDS signals and radio fingerprinting are basically the same today as they have been during the period of interest. Specific details regarding how NSA/CSS exploits such signals, as well as the physical locations where it may access them, would provide adversaries information they need to deny them to NSA/CSS. Targets of interest could develop countermeasures that would render NSA/CSS’s current capability to collect SDS ineffective. (U) Serious damage to national security can be expected if this material were to be declassified.
42. (U//FOUO) Details regarding NSA/CSS ability to perform radio fingerprinting SECRET//SI//REL TO USA, FVEY 50X3 50X6 *75 years from date of material (S//REL TO USA, FVEY) The methods used to perform radio fingerprinting are basically the same today as they have been during the period of interest. Specific details regarding how NSA/CSS exploits such signals, as well as the physical locations where it

TOP SECRET//SI/TK//NOFORN

TOP SEC RET//S1 /TKJ/N OFORJN

may am;ss them, would
provide adversaries
in formal ion they need to deny
them to NSACKS.

Ejieeption:

The faetof, and details
regarding, U.S. and South
Vietnamese use of radio
fingerprinting during the
Vietnam Con fi iet (1 Jan nary
1960-31 Deeember 1975), as
outlined in the Vietnam is
UNCLASSIFIED.

(U) Serious damage to
national seeurity ean be
ex pee ted if this material were
to be dee lass died.

TOP SEC RET//S1/TK//N OFORJN

FOP SE C RET//S1/TK//N ÜFORN


45. (SWSl/REL TO USA, FVEY) Information regarding NSA/CSS ability to collect and process International Commercial (1LC), non-Second Parly government agencies, non-government organizations, and proprietary communications in the radio frequency spectrum via FORNSAT or Terrestrial means S ECRET//S1//RH L 50X3 50X6 *75 years from date of material (S//S1//REL TO USA, FVEY) Fundamental targets have not changed over time and they continue to use the same basic method of communication. If the fact that NS A targeted these entities is released, the commercial providers, government, non- government, and proprietary entities can implement countermeasures that would degrade NSA/CSS's ability to collect and process these communications. (U) Serious damage to national security can he expected if this material were to he declassified.

*75 years from date of material or event, os indicated: (U) 't his indicates [hat the information is
classified for *75 years from date ¿[document is created or until the end of the specified event.

AC RONY MS/DEFINITIONS:

Acoustic - (U) Signals teLned io the production and transmission of sound. Sound is not restricted io audio range
signals

Alphabet Generator - (U) A cipher machine [hat generates a muln pi icily of cipher alphabets from the interaction of
two or more components. Compare to key generator, below.

IIKLJSA - (U) 't he 1946 agreement, now known as UKUSA. In Appendix B (of the 26 February 1946 version) the
section on standardization describes the functional system to he used for the nomenclature of foreign cryptographic
systems. This common system of nomenclature is now called UK.USA system titles*

Close Access - (S//REL TO USA, FVEY) Refers to the targeting, collection, and/or processing of unintentional
emanations from informai ion processing equipment, as well as a program to develop special unique sensors and systems
to collect unintentional (compromising) emanations and/or signals from information processing equipment to exploit
TEMPEST vulnerabilities. Keywords [hat could identify close access equities include (but are not limited to)

FOP SE C RET//S1/TK//N ÜFORN

TOP SECRET//SI/TK//NOFORN

transducer, radiation, conductance, BOOKLET, magnetic probe, acoustic probe, magnetometer, accelerometer,
microphone, transmitted over copper wire, emanations, and unintentional emanations.

Cryptologic Information - (U) Information that describes the target’s use of cryptographic techniques and processes or
of cryptographic systems, equipment, and software and their functions and capabilities, and all cryptographic material.

Cryptanalytic Worksheets - (U) Any records that show methods of analysis of encrypted and/or enciphered
information/data. This includes reports, working aids and papers, instructions, informal technical notes, manuals,
technical exchange letters, handbooks, listings, collateral documents, procedure files, evaluation plans, specific
documentation or records portraying steps, processes, tables, devices, and/or others means employed in cryptanalysis of
target communications.

Depth - (U) Texts are said to be in a depth relationship when the texts were produced by encrypting two or more
different sequences of plain text with the same sequence of key. Related terms include depth reading/stripping, flush
depth, near depth, offset depth, partial depth, and slid depth.

Depth Reading/Stripping - (U) Recovery of plain text and key from messages in depth.

Electromagnetic - (U) Signals that are produced as a result of the use of electrical power

Emanations - (U) Unintentional signals, that, if intercepted and analyzed could disclose the information transmitted,
received, handled, or otherwise processed by information systems equipment. These signals may be acoustic,
electromagnetic, or optical in nature

Generic - (U) Describes emanations and sensors in broad general categories e.g. magnetic, acoustic, power line/signal
line conductance, electric field emissions or other naturally occurring phenomena. Sensors are transducers which
convert physical or electromechanical signals into an electrical signal which can be collected and analyzed.

Indigenous Algorithm, Device, Logic, or System - (U//FOUO) Non-commercial cryptographic information security
system, device or component developed by a SIGINT target for their use. Indigenous will include target modifications
to commercial products and algorithms. If a target-developed version of a commercially available product is
cryptographically indistinguishable from the commercial product, it will be considered commercial.

Key Generator - (U) A cipher machine that generates key from the interaction of two or more components. Compare to

alphabet generator, above.

Listening Post - (U) Physical locations that are close to the target facility and serves as a collection point for the signals
of interest

Low-Grade - (U) Pertaining to a cryptosystem which offers only slight resistance to cryptanalysis; for example:

(1) Playfair ciphers,

(2) Single transposition,

(3) Unenciphered one-part codes

Medium-Grade - (U) Pertaining to a cryptosystem which offers considerable resistance to cryptanalysis; for example:

(1) Strip ciphers,

(2) Double transposition,

(3) Unenciphered two-part codes

RASIN - (U) Radio Signal Notation (RASIN) - A notation assigned permanently and jointly by DIRNSA and second
Party headquarters to a signal after basic signal characteristics have been verified by NSA/CSS or Second Party signals
analysts

Soviet Bloc - (U) Cold War adversaries (Soviet Bloc) up to and including 1950:

Albania, Bulgaria, Czechoslovakia (after February 1948), East Germany (though the German Democratic Republic was

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TOP SECRET//SI/TK//NOFORN

only established on October 1949, any prior German activities in the Soviet Zone should be considered as East German
and within this definition), Hungary, Poland, Romania, USSR, Yugoslavia

System Title - (U//FOUO) Cryptographic system titles are short identification labels used to create a logical reference
mechanism for all cryptographic systems and which identifies the users. Cryptographic system titles are assigned on the
basis of cryptography, target country, and entity.

TEXSIG - (U//FOUO) Technical Extracts of SIGnals (TEXSIG) - A unique designator assigned to a new signal by
a SIGINT field element (USSS or Second Party) or to a signal under analysis or cryptanalytic development by the
headquarters of NSA/CSS and Second Parties (jointly assigned)

TICOM - (U) Target Intelligence Committee (TICOM) - TICOM was formed in London in October 1944 as a joint
U.S./UK activity to interrogate captured enemy COMINT personnel and to acquire enemy COMINT records and
equipment.

TOP SECRET//SI/TK//NOFORN

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