- Classified information
- "Unclassified" redirects here. See also, Unclassified (album).
- "State secrets" redirects here. See also, state secrets privilege.
Classified information is sensitive information to which access is restricted by law or regulation to particular groups of persons. A formal security clearance is required to handle classified documents or access classified data. The clearance process requires a satisfactory background investigation. There are typically several levels (classes) of sensitivity, with differing clearance requirements. This sort of hierarchical system of secrecy is used by virtually every national government. The act of assigning the level of sensitivity to data is called data classification.
A distinction could be made between formal security classification and privacy markings such as "Commercial in confidence".
Some corporations and non-government organizations also assign sensitive information to multiple levels of protection, either from a desire to protect trade secrets, or because of laws and regulations governing various matters such as personal privacy, sealed legal proceedings and the timing of financial information releases.
The purpose of classification is ostensibly to protect information from being used to damage or endanger national security. Classification formalises what constitutes a "state secret" and accords different levels of protection based on the expected damage the information might cause in the wrong hands.
Although the classification systems vary from country to country, most have levels corresponding to the following British definitions (from the highest level to lowest):
Top Secret (TS)
The highest level of classification of material on a national level. Such material would cause "exceptionally grave damage" to national security if made publicly available.
Such material would cause "grave damage" to national security if it were publicly available.
Such material would cause "damage" or be "prejudicial" to national security if publicly available.
Such material would cause "undesirable effects" if publicly available. Some countries do not have such a classification.
Technically not a classification level, but is used for government documents that do not have a classification listed above. Such documents can sometimes be viewed by those without security clearance.
Depending on the level of classification there are different rules controlling the level of clearance needed to view such information, and how it must be stored, transmitted, and destroyed. Additionally, access is restricted on a "need to know" basis. Simply possessing a clearance does not automatically authorize the individual to view all material classified at that level or below that level. The individual must present a legitimate "need to know" in addition to the proper level of clearance.
In addition to the general risk-based classification levels above, often there are additional constraints on access, such as (in the U.S.) Special Intelligence (SI), which protects intelligence sources and methods, No Foreign dissemination (NOFORN), which restricts dissemination to U.S. nationals, and Originator Controlled dissemination (ORCON), which ensures that the originator can track possessors of the information. Documents in some compartments are marked with specific "code words" in addition to the classification level.
Government information about nuclear weapons such as nuclear warheads often has an additional marking to show it contains such information.
Sharing classified information between countries
When a government agency or group shares information between an agency or group of other country’s government they will generally employ a special classification scheme that both parties have previously agreed to honour.
In example the marken ATOMAL, is applied to U.S. RESTRICTED DATA or FORMERLY RESTRICTED DATA and United Kingdom ATOMIC information that has been released to NATO. ATOMAL information is marked COSMIC TOP SECRET ATOMAL (CTSA), NATO SECRET ATOMAL (NSAT), or NATO CONFIDENTIAL ATOMAL (NCA).
In cases where a country wishes to share classified information bilaterally (or multilaterally) with a country that has a sharing agreement, the information is with the countries it can be shared with. Those countries would have to maintain the classification of the document at the level originally classified (TOP-SECRET, SECRET, etc.) with the appropriate caveat (USNZ, AUSGE, CANUK, etc.).
For example, sensitive information shared amongst NATO allies has four levels of security classification; from most to least classified:
- COSMIC TOP SECRET (CTS),
- NATO SECRET (NS),
- NATO CONFIDENTIAL (NC), and
- NATO RESTRICTED (NR).
A special case exists with regard to NATO UNCLASSIFIED (NU) information. Documents with this marking is NATO property (copyright) and must not be made public without NATO permission. In general documents with this classification, aren't cleared for internet-transmission either, unless clearly marked with RELEASABLE FOR INTERNET TRANSMISSION. Documents that can be made public however, should be clearly marked with NON SENSITIVE INFORMATION RELEASABLE TO THE PUBLIC.
In addition to the above classification levels NATO operates with
- COSMIC TOP SECRET - A
This level is given to people who need to have access to the joined Atomic program of NATO. This level is never given permanently to anyone, regardless of jobtitle - e.g. President of the US etc. It is only given for short periods of time, when needed.
- European Commission, has 5 levels, EU TOP SECRET, EU SECRET, EU CONFIDENTIAL, EU RESTRICTED, and EU COUNCIL / COMMISSION. (Note that usually the French term is used)
- OCCAR, a European defence organisation, has three levels of classification: OCCAR SECRET, OCCAR CONFIDENTIAL, OCCAR RESTRICTED.
Most countries employ some sort of classification system for certain government information. For example, in Canada, information that the U.S. would classify SBU (Sensitive but Unclassified) is called "protected" and further subcategorised into levels A, B, and C.
National security (NS) classifications in Australia comprise TOP SECRET, SECRET, CONFIDENTIAL, RESTRICTED and UNCLASSIFIED. Background checks for access to TOP SECRET material are carried out at either of two levels: at TOP SECRET NEGATIVE VETTING (TSNV), or at the more stringent and expensive TOP SECRET POSITIVE VETTING (TSPV) level, depending on the extent of required access to TOP SECRET material and on the potential damage to national security should such material be disclosed to unauthorised parties. Most background checks for access to TOP SECRET material are carried out at the TOP SECRET NEGATIVE VETTING level.
Australia also has a non-national security (NNS) classification system that is used in areas of the Federal Government not directly related to national security matters. This system is used for information whose compromise would not directly threaten the security of the nation, but the release of which could threaten the security or interests of individuals, groups, commercial entities, government business and interests, or the safety of the community.
- HIGHLY PROTECTED, which broadly corresponds to SECRET in the national security system.
- PROTECTED, which broadly corresponds to CONFIDENTIAL in the national security system.
- X-IN-CONFIDENCE, which broadly corresponds to RESTRICTED in the national security system. Examples of X-IN-CONFIDENCE markings include, among others, STAFF-IN-CONFIDENCE, COMMERCIAL-IN-CONFIDENCE and LEGAL-IN-CONFIDENCE.
In addition, documents marked CABINET-IN-CONFIDENCE, relating to discussions in Federal Cabinet, are treated as PROTECTED due to its higher sensitivity.
Although NNS markings broadly map to NS classifications, the NS classifications hold precedence. I.e. If a need to know is established, a person with a SECRET clearance may view HIGHLY PROTECTED information, however, not vice versa.
In Brazil, a top secret (Ultrassecreto) government-issued document may be classified for a period of 25 years, which may be extended up to another 25 years. Thus, no document remains classified for more than 50 years. This is mandated by the 2011 Information Access Law (Lei de Acesso à Informação), a change from the previous rule, under which documents could have their classification time length renewed indefinitely, effectively shuttering state secrets from the public. The new law applies retroactively to existing documents.
Background and hierarchy
There are 2 main type of sensitive information designation used by the Government of Canada: Classified and Designated. The access and protection of both types of information is governed by the Security of Information Act, effective December 24, 2001, replacing the Official Secrets Act 1981. To access the information, a person must have the appropriate level of clearance and a Need to know.
Special operational information
SOI is not a classification of data per se. It is defined under the Security of Information Act, and unauthorised release of such information constitutes a higher breach of trust, with penalty of life imprisonment.
- military operations in respect of a potential, imminent or present armed conflict
- the identity of confidential source of information, intelligence or assistance to the Government of Canada
- tools used for information gathering or intelligence
- the object of a covert investigation, or a covert collection of information or intelligence
- the identity of any person who is under covert surveillance
- encryption and cryptographic systems
- information or intelligence to, or received from, a foreign entity or terrorist group
Classified information can be designated Top Secret, Secret or Confidential. These classifications are only used on matters of national interest.
- Top Secret: This applies when compromise might reasonably cause exceptionally grave injury to the national interest. The possible impact must be great, immediate and irreparable.
- Secret: This applies when compromise might reasonably cause serious injury to the national interest.
- Confidential: When disclosure might reasonably cause injury to the national interest.
Designated information is not classified. Designated information pertains to any sensitive information that does not relate to national security and cannot be disclosed under the access and privacy legislation because of the possible injury to particular public or private interests.
- Protected C (Extremely Sensitive designated information): is used to protect extremely sensitive information if compromised, could reasonably be expected to cause extremely grave injury outside the national interest. Examples could include bankruptcy, identities of informants in criminal investigations, etc.
- Protected B (Particularly Sensitive designated information): is used to protect information that could cause severe injury or damage to the people or group involved if it was released. Examples include medical records, annual personnel performance reviews, etc.
- Protected A (Low-Sensitive designated information): is applied to low sensitivity information that should not be disclosed to the public without authorisation and could reasonably be expected to cause injury or embarrassment outside the national interest. Example of Protected A information could include employee number, pay deposit banking information, etc.
People's Republic of China
The Criminal Law of the People's Republic of China (which is not operative in the Special Administrative Regions of Hong Kong and Macao) makes it a crime to release a state secret. Regulation and enforcement is carried out by the National Administration for the Protection of State Secrets.
Under the 1989 "Law on Guarding State Secrets," state secrets are defined as those that concern:
- Major policy decisions on state affairs;
- The building of national defence and in the activities of the armed forces;
- Diplomatic activities and in activities related to foreign countries and those to be maintained as commitments to foreign countries;
- National economic and social development;
- Science and technology;
- Activities for preserving state security and the investigation of criminal offences; and
- Any other matters classified as "state secrets" by the national State Secrets Bureau.
Secrets can be classified into one of three categories:
- Top secret (绝密): Defined as "vital state secrets whose disclosure would cause extremely serious harm to state security and national interests";
- Highly secret (机密): Defined as "important state secrets whose disclosure would cause serious harm to state security and national interests"; and
- Secret (秘密): Defined as "ordinary state secrets whose disclosure would cause harm to state security and national interests".
In France, classified information defined by article 413-9 of the Penal Code. The three levels of military classification are
- Confidentiel Défense (Confidential Defence): Information deemed potentially harmful to national defence, or that could lead to uncovering an information classified at a higher level of security.
- Secret Défense (Secret Defence): Information deemed very harmful to national defence. Such information cannot be reproduced without authorisation from the emitting authority, except in exceptional emergencies.
- Très Secret Défense (Very Secret Defence): Information deemed extremely harmful to national defence, and relative to governmental priorities in national defence. No service or organisation can elaborate, process, stock, transfer, display or destroy information or protected supports classified at this level without authorisation from the Prime Minister or the national secretary for National Defence. Partial or exhaustive reproduction is strictly forbidden.
Less sensitive information is "protected". The levels are
- Non Protégé (unprotected)
- Diffusion restreinte administrateur ("administrative restricted information")
- Diffusion restreinte ("restricted information")
- Confidentiel personnels Sous-Officiers ("Confidential non-commissioned officers")
- Confidentiel personnels Officiers ("Confidential officers")
A further mention, "spécial France" (reserved France) restricts the document to French citizens (in its entirety or by extracts). This is not a classification level.
Declassification of documents can be done by the Commission consultative du secret de la défense nationale (CCSDN), an independent authority. Transfer of classified information is done with double envelopes, the outer layer being plastified and numbered, and the inner in strong paper. Reception of the document involves examination of the physical integrity of the container and registration of the document. In foreign countries, the document must be transferred through specialised military mail or diplomatic bag. Transport is done by an authorised convoyer or habilitated person for mail under 20 kg. The letter must bear a seal mentioning "PAR VALISE ACCOMPAGNEE-SACOCHE". Once a year, ministers have an inventory of classified information and supports by competent authorities.
Once their usage period is expired, documents are transferred to archives, where they are either destroyed (by incineration, crushing or electrical overtension), or stored.
In case of unauthorized release of classified information, competent authorities are the Ministry of Interior, the Haut fonctionnaire de défense et de sécurité ("high civil servant for defence and security") of the relevant ministry, and the General secretary for National Defence. Violation of such secrets is an offence punishable with 7 years of imprisonment and a 100 000 Euro fine; if the offence is committed by imprudence or negligence, the penalties are 3 years of imprisonment and a 45 000 Euro fine.
The Security Bureau is responsible for developing policies in regards to the protection and handling of confidential government information. In general, the system used in Hong Kong is very similar to the UK system, developed from the Colonial Hong Kong era.
Four classifications exists in Hong Kong, from highest to lowest in sensitivity:
- Top Secret (高度機密)
- Secret (機密)
- Confidential (保密)
- Temporary Confidential (臨時保密)
- Restricted (限閱文件/內部文件)
- Restricted (staff) (限閱文件(人事))
- Restricted (tender) (限閱文件 (投標))
- Restricted (administration) (限閱文件 (行政))
New Zealand uses the Restricted classification, which is lower than Confidential. People may be given access to Restricted information on the strength of an authorisation by their Head of Department, without being subjected to the background vetting associated with Confidential, Secret and Top Secret clearances. New Zealand's security classifications and the national-harm requirements associated with their use are roughly similar to those of the United States.
In addition to national security classifications there are two additional security classifications, In Confidence and Sensitive, which are used to protect information of a policy and privacy nature. There are also a number of information markings used within ministries and departments of the government, to indicate, for example, that information should not be released outside the originating ministry.
Because of strict privacy requirements around personal information, personnel files are controlled in all parts of the public and private sectors. Information relating to the security vetting of an individual is usually classified at the In Confidence level.
In the Russian Federation, a state secret (Государственная тайна) is information protected by the state on its military, foreign policy, economic, intelligence, counterintelligence, operational and investigative and other activities, dissemination of which could harm state security.
The Swedish classification has been updated due to increased NATO/PfP co-operation. All classified defence documents will now have both a Swedish classification (Kvalificerat Hemlig or Hemlig), and an English classification (Top Secret, Secret, Confidential or Restricted).
The United Kingdom currently uses five levels of classification — from lowest to highest, they are: PROTECT, RESTRICTED, CONFIDENTIAL, SECRET and TOP SECRET (formerly MOST SECRET). Those working with such material should have the relevant security clearance and often are required to sign to confirm their understanding and acceptance of the Official Secrets Acts 1911 to 1989, although the Act applies in the same way regardless of signature. PROTECT is not in itself a security protective marking level (such as RESTRICTED or greater), but is used to indicate information which should not be disclosed because, for instance, the document contains tax, or national insurance or other personal information.
Government documents without a classification may be marked as UNCLASSIFIED or NOT PROTECTIVELY MARKED.
The U.S. classification system is currently established under Executive Order 13292 and has three levels of classification — Confidential, Secret, and Top Secret. The U.S. had a Restricted level during World War II but no longer does. U.S. regulations state that information received from other countries at the Restricted level should be handled as Confidential. A variety of markings are used for material that is not classified, but whose distribution is limited administratively or by other laws, e.g., For Official Use Only (FOUO), or Sensitive but Unclassified (SBU). The Atomic Energy Act of 1954 provides for the protection of information related to the design of nuclear weapons. The term "Restricted Data" is used to denote certain nuclear technology. Information about the storage, use or handling of nuclear material or weapons is marked "Formerly Restricted Data." These designations are used in addition to level markings (Confidential, Secret and Top Secret). Information protected by the Atomic Energy Act is protected by law and information classified under the Executive Order is protected by Executive privilege.
Table of equivalent classification markings in various countries
(State) Top Secret Secret Confidential Restricted Albania Teper Sekret Sekret Konfidencial I Kufizuar Argentina Estrictamente Secreto y Confidencial Secreto Confidencial Reservado Australia Top Secret Secret Confidential Restricted Austria Streng Geheim Geheim Vertraulich Eingeschränkt Belgium (Dutch) Zeer Geheim Geheim Vertrouwelijk Beperkte Verspreiding Belgium (French) Très Secret Secret Confidentiel Diffusion restreinte Bolivia Supersecreto
or Muy Secreto
Secreto Confidencial Reservado Bosnia Strogo Povjerljivo Tajno Konfidencialno Restiktirano Brazil Ultra Secreto Secreto Confidencial Reservado Bulgaria Строго секретно Секретно Поверително За служебно ползване Cambodia Sam Ngat Bamphot Sam Ngat Roeung Art Kambang Ham Kom Psay Canada Top Secret/Très secret Secret/Secret Confidential/Confidentiel Protected A, B or C / Protégé A, B ou C Chile Secreto Secreto Reservado Reservado China, People's Republic of Juémì (绝密) Jīmì (机密) Mìmì (秘密) Nèibù (内部) Colombia Ultrasecreto Secreto Confidencial Reserva del sumario Costa Rica Alto Secreto Secreto Confidencial Croatia Vrlo tajno Tajno Povjerljivo Ograničeno Czech Republic Přísně tajné Tajné Důvěrné Vyhrazené Denmark Yderst Hemmeligt Hemmeligt Fortroligt Til Tjenestebrug
(thin Black border)
Ecuador Secretisimo Secreto Confidencial Reservado Egypt Sirriy lil-Ġāyah
El Salvador Ultra Secreto Secreto Confidencial Reservado Estonia Täiesti salajane Salajane Konfidentsiaalne Piiratud Ethiopia Yemiaz Birtou Mistir Mistir Kilkil Finland Erittäin salainen (TLL I) Salainen (TLL II) Luottamuksellinen (TLL III) Viranomaiskäyttö (TLL IV) France Très secret défense Secret défense Confidentiel défense Diffusion restreinte Germany Streng Geheim Geheim VS-Vertraulich VS-Nur für den Dienstgebrauch Greece Άκρως Απόρρητον Απόρρητον Εμπιστευτικόν Περιορισμένης
Guatemala Alto Secreto Secreto Confidencial Reservado Haiti Top Secret Secret Confidential Reserve Honduras Super Secreto Secreto Confidencial Reservado Hong Kong Top Secret, 高度機密 Secret, 機密 Confidential, 保密 Restricted, 內部文件/限閱文件 Hungary Szigorúan Titkos Titkos Bizalmas Korlátozott Terjesztésű India (Hindi) परम गुप्त (Param Gupt) गुप्त (Gupt) गोपनीय (Gopniya) प्रतिबंधित/सीमित (Pratibandhit/seemit) India (English) Top Secret Secret Confidential Restricted Indonesia Sangat Rahasia Rahasia Rahasia Dinas Terbatas Iran Bekolli serri به کلّى سرّى Serri سرّى Kheili Mahramaneh خيلى محرمانه Mahramaneh محرمانه Iraq Sirriy lil-Ġāyah
Iceland Algert Leyndarmál Leyndarmál Þjónustuskjal Trúnaðarmál Ireland (Irish language) An-sicreideach Sicreideach Runda Srianta Israel Sodi Beyoter
Italy Segretissimo Segreto Riservatissimo Riservato Japan Kimitsu, 機密 Gokuhi, 極秘 Hi, 秘 Toriatsukaichuui, 取り扱い注意 Jordan Maktūm Ǧiddan
Korea, South I(Il)-Kup Bi Mil, 1급비밀 II(I)-Kup Bi Mil, 2급비밀 III(Sam)-Kup Bi Mil, 3급비밀 Dae Woi Bi, 대외비 Korea, North Unknown, 익명의 Unknown, 익명의 Unknown, 익명의 Unknown, 익명의 Laos Lup Sood Gnod Kuam Lup Kuam Lap Chum Kut Kon Arn Latvia Sevišķi slepeni Slepeni Konfidenciāli Dienesta vajadzībām Lebanon Tres Secret Secret Confidentiel Lithuania Visiškai Slaptai Slaptai Konfidencialiai Riboto Naudojimo Malaysia Rahsia Besar Rahsia Sulit Terhad Mexico Ultra Secreto Secreto Confidencial Restringido Montenegro Strogo Tajno Tajno Povjerljivo Interno Netherlands Zeer Geheim Geheim Vertrouwelijk Departementaal Vertrouwelijk New Zealand Top Secret Secret Confidential Restricted Nicaragua Alto Secreto Secreto Confidencial Reservado Norway STRENGT HEMMELIG HEMMELIG KONFIDENSIELT BEGRENSET Pakistan (Urdu) Intahai Khufia Khufia Sigh-e-Raz Barai Mahdud Taqsim Pakistan (English) Top Secret Secret Confidential Restricted Paraguay Secreto Secreto Confidencial Reservado Peru Estrictamente Secreto Secreto Confidencial Reservado Philippines Top Secret Secret Confidential Restricted Poland Ściśle tajne Tajne Poufne Zastrzeżone Portugal Muito Secreto Secreto Confidencial Reservado Romania Strict Secret de Importanţă Deosebită Strict Secret Secret Secret de serviciu Russia Особой важности
(вариант: Совершенно Секретно (Sovershenno Sekretno))
(вариант: Секретно (Sekretno))
(вариант: Не подлежит оглашению
(Конфиденциально) (Ne podlezhit oglasheniyu (Konfidentsial'no))
Для Служебного Пользования (ДСП)
(Dlya Sluzhebnogo Pol'zovaniya)
Saudi Arabia Saudi Top Secret Saudi Very Secret Saudi Secret Saudi Restricted Serbia Latin: Državna tajna
Cyrillic: Државна тајна
Latin: Strogo poverljivo
Cyrillic: Строго поверљиво
Singapore Top Secret Secret Confidential Restricted Slovak Republic Prísne tajné Tajné Dôverné Vyhradené Slovenija Strogo tajno Tajno Zaupno Interno Spain Secreto Reservado Confidencial Difusión Limitada Sweden Kvalificerat Hemlig (KH); Hemlig/Top Secret (H/TS) Hemlig (H); Hemlig/Secret H/S) Hemlig/Confidential (H/C) Hemlig/Restricted (H/R) Switzerland Geheim / Secret Vertraulich / Confidentiel Dienstlich / Interne au service Thailand Lap thi sut (ลับที่สุด) Lap mak (ลับมาก) Lap (ลับ) Turkey Çok Gizli Gizli Özel Hizmete Özel South Africa (English) Top Secret Secret Confidential Restricted South Africa (Afrikaans) Uiters Geheim Geheim Vertroulik Beperk Ukraine Особливої важливості Цілком таємно Таємно Для службового користування United Kingdom TOP SECRET SECRET CONFIDENTIAL RESTRICTED United States Top Secret Secret Confidential For Official Use Only Uruguay Ultra Secreto Secreto Confidencial Reservado Vietnam Tuyệt Mật Tối Mật Mật Phổ Biến Hạn Chế NATO Cosmic Top Secret NATO Secret NATO Confidential NATO Restricted European Union (EU) TRES SECRET UE / EU TOP SECRET SECRET UE / EU SECRET CONFIDENTIEL UE / EU CONFIDENTIAL RESTREINT UE / EU RESTRICTED Western European Union (WEU) FOCAL TOP SECRET WEU SECRET WEU CONFIDENTIAL WEU RESTRICTED Euratom EURA TOP SECRET EURA SECRET EURA CONFIDENTIAL EURA RESTRICTED
Original source: NISPOM Appendix B ¹ In addition, Finland uses label Salassa pidettävä, "to be kept secret" for information that is not classified but must not be revealed on some other basis than national security. (E.g. privacy, trade secrets etc.)
Private corporations often require written confidentiality agreements and conduct background checks on candidates for sensitive positions. In the U.S. the Employee Polygraph Protection Act prohibits private employers from requiring lie detector tests, but there are a few exceptions. Policies dictating methods for marking and safeguarding company-sensitive information (e.g. "IBM Confidential") are common and some companies have more than one level. Such information is protected under trade secret laws. New product development teams are often sequestered and forbidden to share information about their efforts with un-cleared fellow employees, the original Apple Macintosh project being a famous example. Other activities, such as mergers and financial report preparation generally involve similar restrictions. However, corporate security generally lacks the elaborate hierarchical clearance and sensitivity structures and the harsh criminal sanctions that give government classification systems their particular tone.
Traffic Light Protocol
The Traffic Light Protocol was developed by the G8 countries to enable the sharing of sensitive information between government agencies and corporations. This protocol has now been accepted as a model for trusted information exchange by over 30 other countries. The protocol provides for four "information sharing levels" for the handling of sensitive information.
- ^ http://www.nsa.gov/public_info/_files/uss_liberty/attack_sigint.pdf
- ^ http://etuce.homestead.com/Access_to_EU_commission_documents_1.pdf
- ^ http://www.fco.gov.uk/Files/kfile/306652_CM6554.pdf
- ^ Security of Information Act
- ^ Non-Insured Health Benefits Program Privacy Code
- ^ Security Policy - Manager's Handbook
- ^ Confidences of the Queen's Privy Council for Canada
- ^ Standing Committee of the National People's Congress, "Law on Guarding State Secrets" (中华人民共和国保守国家秘密法), promulgated 1988 and effective 1989.
- ^ a b Translation per Human Rights in China, State Secrets: China's Legal Labyrinth, (2007).
- ^ Article 413-9, Legifrance
- ^ [dead link]
- ^ LCQ3: Equal Opportunities Commission
- ^ http://www.cabinetoffice.gov.uk/spf/faqs.aspx
- ^ https://www.aivd.nl/aspx/download.aspx?file=/contents/pages/95299/leidraadaanwijzenvertrouwensfuncties.pdf
- ^ https://www.dss.mil/portal/ShowBinary/BEA%20Repository/new_dss_internet/isp/fac_clear/download_nispom.html
- ^ http://www.privacyrights.org/fs/fs16-bck.htm
- ^ http://www.oecd.org/dataoecd/25/10/40761118.pdf
- ^ http://marc.info/?l=bugtraq&m=122754275122010&w=2
- US "NISPOM" manual, explaining rules on classified information among other things - full title is "National Industrial Security Program Operating Manual".
- Marking Classified National Security Information ISOO booklet PDF
- Defence Vetting Agency. Carries out national security checks in the UK.
- Los Alamos table of equivalent US and UK classifications
- The Black Vault - a database of more than a half million declassified pages on many different topics, all acquired through the FOIA
- The National Security Archive - a collection of declassified documents acquired through the FOIA
- Lerner, Brenda Wilmoth & K. Lee Lerner, eds. Terrorism: essential primary sources. Thomson Gale, 2006. ISBN 978-1-4144-0621-3 Library of Congress. Jefferson or Adams Bldg General or Area Studies Reading Rms LC Control Number: 2005024002.
- Peter Galison, Removing Knowledge in Critical Inquiry n°31 (Autumn 2004)
- Parlament of Serbia, Law on confidentiality of data. (Serbian)
- Parlament of Montenegro, Law on confidentiality of data. (Serbian)
- Christopher Moran, Classified: Secrecy and the State in Modern Britain (Cambridge: Cambridge University Press, 2012).
Wikimedia Foundation. 2010.