Executive Order 10290—Prescribing Regulations Establishing Minimum Standards for the Classification, Transmission, and Handling, by Departments and Agencies of the Executive Branch, of Official Information Which Requires Safeguarding in the Interest of the Security of the United States
WHEREAS it is necessary, in order to protect the national security of the United States, to establish a system for the safeguarding of official information the unauthorized disclosure of which would or could harm, tend to impair, or otherwise threaten the security of the nation; and
WHEREAS it is desirable and proper that minimum standards for procedures designed to protect the national security against such unauthorized disclosure be uniformly applicable to all departments and agencies of the Executive Branch of the Government and be known to and understood by those who deal with the Federal Government; and
WHEREAS the furnishing of information to the public about government activities will be facilitated by clear identification and marking of those matters the safeguarding of which is required in the interest of national security;
NOW, THEREFORE, by virtue of the authority vested in me by the Constitution and statutes, and as President of the United States, the regulations attached hereto, entitled "Regulations Establishing Minimum Standards for the Classification, Transmission, and Handling, by Departments and Agencies of the Executive Branch, of Official Information Which Requires Safeguarding in the Interest of the Security of the United States," are hereby prescribed for application throughout the Executive Branch of the Government to the extent not inconsistent with law.
Such regulations shall take effect thirty days after their publication in the FEDERAL REGISTER.
All citizens of the United States who may have knowledge of or access to classified security information are requested to observe the standards established in such regulations with respect to such information and to join with the Federal Government in a concerted and continuing effort to prevent disclosure of such information to persons who are inimical to the interests of the United States.
REGULATIONS ESTABLISHING MINIMUM STANDARDS FOR THE CLASSIFICATION, TRANSMISSION, AND HANDLING, BY DEPARTMENTS AND AGENCIES OF THE EXECUTIVE BRANCH, OF OFFICIAL INFORMATION WHICH REQUIRES SAFEGUARDING IN THE INTEREST OF THE SECURITY OF THE UNITED STATES
Part I - General
1. Purpose and scope. a. The sole purpose of these regulations is to establish minimum standards, which are to be maintained in all cases where higher standards are not established by appropriate authority, for identifying and protecting information the safeguarding of which is necessary in order to protect the security of the United States; and the minimum standards established by these regulations shall not supersede any higher standards established by appropriate authority.
b. Nothing in these regulations shall be construed to replace, change, or otherwise be applicable with respect to any material or information protected against disclosure by any statute.
c. Nothing in these regulations shall be construed to authorize the dissemination, release, handling or transmission of classified information contrary to the provisions of any law, Executive order, or Presidential directive which restricts the dissemination, release, handling, or transmission of such information.
d. These regulations shall apply only to classified security information as defined in paragraph 4 of Part II hereof, and the terms "classified security information," "security classification," "classify," "declassify," "downgrade," "upgrade," "appropriate classifying authority" and "marking," as used in these regulations, apply or relate only to official information of the United States Government which requires safeguarding in order to protect the national security.
2. Categories of classified security information. There shall be four categories of classified security information which, in descending order of importance to national security, shall carry one of the following designations: "To Secret"; "Secret"; "Confidential"; and "Restricted"; in addition to being specifically identified as "Security Information." No other classification or classifications shall be used to designate classified security information.
3. Non-security information. Information, official or otherwise, shall not be classified under these regulations unless it requires protective safeguarding in the interest of the security of the United States. The use of any one of the four security classifications herein prescribed combined with the identification "Security Information," shall be strictly limited to classified security information
PART II-DEFINITIONS
4. Classified security information. The term "classified security information" as used herein means official information the safeguarding of which is necessary in the interest of national security, and which is classified for such purpose by appropriate classifying authority.
5. Information. The term "information" as used herein means knowledge which can be communicated, either orally or by means of material.
6. Material. The term "material" as used herein means any document, product, or substance on or in which information may be recorded or embodied.
7. Document. The term "document" as used herein means any recorded information regardless of its physical form or characteristics, and includes, but is not limited to, the following: (1) All written material, whether handwritten, printed, or typed; (2) all painted, drawn or engraved material; (3) all sound or voice recordings; (4) all printed photographs and exposed or printed film, sill or motion picture, and (5) all reproductions of the foregoing, by whatever process reproduced.
8. Product and substance. The terms "product" and "substance" as used herein mean any item of material (other than a document) from which information may be obtained; apply to items in all stages of development, processing, or construction; and include elements, ingredients, components, accessories, fixtures, dies, models, and mock-ups associated with such items.
9. Agency. The term "agency" as used herein means any department or establishment within the Executive Branch, including any government corporation that is operated as an instrumentality of the Federal Government.
10. Unclassified information. The term "unclassified information" as used herein means information determined by the appropriate classifying authority not to require the procedural safeguards provided by these regulations and therefore not included in one of the aforementioned security classifications.
11. Cryptographic system. The term "cryptographic system" as used herein means any document, product, or method employed to change information from plain language form into coded form, or to change information from coded form into plain language form.
12. Serial matter. The term "serial matter" as used herein means any material to which a serial number is assigned and which is accounted for at prescribed intervals and upon specified occasions.
13. Telegram. The term "telegram" as used herein means any document recording information transmitted or for transmission by telegraph, telephone, cable, radio or other electrical means of transmission.
14. Classify. The term "classify" as used herein means to assign information to one of the four security classification categories after determination has been made that the information requires the security protection provided by these regulation.
15. Security classification. The term "security classification" as used herein means the category into which information falls after being classified as specified in paragraph 2 of Part I hereof. Extreme care should be exercised to insure that a particular security classification is assigned only to such information as requires the degree of protection made applicable by these regulations to that classification.
16. Declassify. The term "declassify" as used herein means to remove the security classification.
17. Downgrade. The term "downgrade" as used herein means to assign a lower security classification than that previously assigned.
18. Upgrade. The term "upgrade" as used herein means to assign a higher security classification than that previously assigned.
19. Appropriate classifying authority-a. In general. The term "appropriate classifying authority" as used herein means the head of the originating agency and those whom he has authorized to classify, declassify, upgrade or downgrade information pursuant to these regulations.
b. Material officially transferred from originating agency to another agency. In the case of information transferred by or pursuant to statute or Executive order from one agency to another for the latter's use and as part of its official files, as distinguished from transfers merely for purposes of storage, the receiving agency shall be deemed to be the "appropriate classifying authority" for all purposes under these regulations.
c. Material of defunct agency not officially transferred to another agency. When any agency has in its possession, on or after the effective date of these regulations, any classified security information which is then, or thereafter becomes, five years old and it appears (1) that such information originated in an agency which has since become defunct and whose records, files and other material have not been officially transferred to another agency within the meaning of subsection "b" above, or (2) that it is impossible for the possessing agency to identify the originating agency, and (3) a review of the information indicates that it should be downgraded or declassified, the said possessing agency shall have power under these regulations to declassify or downgrade such information. If it appears probable that another agency may have a substantial interest in the question whether the security classification of any particular information should be maintained, the possessing agency shall not exercise the power conferred upon it by this subsection until thirty days after the possessing agency has notified such other agency of the nature of the information and of its intention to declassify or downgrade the same. During the thirty-day period the other agency may, if it so desires, express its objections to declassifying or downgrading the particular information, but the power to make the ultimate decision shall reside in the possessing agency.
20. Marking. The term "marking" as used herein means the physical act of indicating on classified security information the assigned classification or change therein.
21. Record material. The term "record material" as used herein means all books, papers, maps, photographs, or other documentary materials, regardless of physical form or characteristics, made or received by an agency of the United States Government in connection with the transaction of public business and preserved or appropriated for preservation by that agency or its legitimate successor as evidence of the organization, functions, policies, operations, decisions, procedures, or other activities of any agency of the Government, or because of the informational value of the data contained therein.
22. Non-record material. The term "non-record material" as used herein means extra copies and duplicates the use for which is essentially temporary, including shorthand notes, used carbon paper, preliminary drafts, and other material of similar nature.
PART III-RESPONSIBILITIES
23. All personnel in the Executive Branch. A. The responsibility for the protection, pursuant to these regulations, of classified security information shall rest upon each individual in the Executive Branch of the Government having such information or knowledge thereof, no matter how that information or knowledge was obtained.
b. Each individual in the Executive Branch shall be directly responsible for familiarizing himself with and adhering to all regulations applicable to him which are issued for the protection of classified security information.
24. Authority for heads of agencies to delegate. The ultimate responsibility for the safeguarding of classified security information within an agency shall remain with and rest upon the head of the agency, but the head of an agency may delegate the performance of any or all of the functions charged to him herein, including:
a. The issuance of such additional instructions on the safeguarding of classified security information as requirements of his agency may dictate;
b. Maintenance of the security of his agency's messenger-courier systems for transmission of classified security information;
c. Authorization of appropriate officials within his agency to assign information to the proper security classification under these regulations. Authorizations to classify security information as "Top Secret" or "Secret" shall be held to the minimum necessary for the performance of required activities, and shall be maintained at a high level within the agency. The authorizations to classify security information as "Top Secret" shall be substantially more limited in number than those for "Secret" and shall be restricted to those officials whose functional requirements are such that they must have that authority;
d. Designation of those authorized to receive "Top Secret" security information;
e. Designation of officials responsible for "Top Secret" security information control;
f. Designation of individuals responsible for the security programs in the various organizational units of the agency;
g. Appropriate investigation and clearance of personnel who are to have access to classified security information;
h. Maintenance within his agency of a continuing review of the use of security classifications to insure uniform and proper application;
i. Establishment of procedures governing dissemination of classified security information outside his agency;
j. Establishment of procedures governing changes in security classification and the destruction of classified security information;
k. Thorough indoctrination of all individuals of his agency in security regulations and procedures; and
l. Issuance of additional instructions pertaining to communications security, serial matter, Restricted Data (as hereinafter used), and other subjects requiring additional regulations.
PART IV-RULES GOVERNING SECURITY CLASSIFICATION, UPGRADING, DOWNGRADING, AND DECLASSIFICATION
25. General Classification Principles-a. Uniformity of application of classification. Uniformity of application of classification shall be a requirement for the proper safeguarding of classified security information. In accordance with paragraphs 2 and 3 of Part I hereof, and in order to preserve the integrity of the security classifications "Top Secret," "Secret," "Confidential," and "Restricted," when combined with the identification "Security Information," these classifications shall be used only for the purpose of identifying information which must be safeguarded to protect the national security.
b. Use of lowest consistent classification. To avoid overclassification and depreciation of the importance of properly classified security information and to avoid unnecessary delay in the handling and transmission of documents and other material, security information shall be assigned the lowest security classification consistent with its proper protection. Use of the classification "Top Secret" combined with the identification "Security Information," shall be held at an absolute minimum. Such classification shall be given only to information which plainly requires the highest degree of protection in the interest of national security. The major criterion for the assignment of this classification shall be recognition of the fact that unauthorized disclosure of information so classified would or could cause exceptionally grave danger to the national security. The classification "Secret" combined with the identification "Security Information" shall be given only to information which requires extraordinary protection in the interest of national security. The classification "Confidential" combined with the identification "Security Information" shall be given to such information as requires careful protection in order to prevent disclosures which might harm national security. The classification "Restricted" combined with the identification "Security Information" shall be applied to information having such bearing upon national security as to require protection against unauthorized use or disclosure, particularly information which should be limited to official use.
c. Special statutory use of term "Restricted Data." The term "Restricted" as used herein shall not be confused with the term "Restricted Data," defined in the Atomic Energy Act of August 1, 1946 (60 Stat. 766, c. 724, sec. 10(b)(1); 42 U.S.C. sec. 1810(b)(1)) as follows:
The term "Restricted Data" as used in this section means all data concerning the manufacture or utilization of atomic weapons, the production of fissionable material, or the use of fissionable material in the production of power, but shall not include any data which the Commission from time to time determines may be published without adversely affecting the common defense and security.
Nothing in these regulations shall be construed to authorize the classification, downgrading or declassification of "Restricted Data," except by the Atomic Energy Commission in conformity with the provisions of the Atomic Energy Act.
26. Special classification rules-a. Change in classification of information. No change shall be made in the assigned classification of security information without the consent of the appropriate classifying authority; extracts from or paraphrases of classified documents shall likewise be maintained in the assigned security classification unless the consent of the appropriate classifying authority to downgrade or declassify such extract or paraphrase is secured, or unless the agency making such extracts knows positively that they bear a security classification lower than that of the document from which extracted, or that they are not classified.
b. Classified telegrams shall not be referred to, extracted from, paraphrased, downgraded, declassified, or disseminated except in accordance with special regulations used by the head of the originating agency.
Classified telegrams transmitted over cryptographic systems shall be handled in accordance with the regulations of the transmitting agency.
c. Information originated by a foreign government. Information of a classified nature originated by a foreign government and furnished to the United States by that government shall be assigned a security classification which will assure a degree or protection equivalent to or greater than that required by the originating government.
d. Documents in general. Documents shall be classified according to their own content and not necessarily according to their relationship to other documents. References to classified material which do not reveal classified security information shall not be classified.
e. Physically connected documents. The classification of a file or group of physically connected documents shall be at least as high as that of the most highly classified document therein. Documents separated from the file or group shall be handled in accordance with their individual security classification.
f. Multiple classification. A document, product, or substance shall bear a classification at least as high as that of its highest classified components. The document, product, or substance shall bear only one over-all security classification, notwithstanding that pages, paragraphs, sections, or components may bear different classifications.
g. A letter transmitting security information shall be classified at least as high as its highest classified enclosure.
27. Upgrading-a. When information is upgraded, the appropriate classifying authority shall, so far as possible, notify all addressees to whom the information was originally transmitted.
b. If the recipient of information believes that its assigned classification is not sufficiently protective, he shall safeguard it in accordance with the classification he deems appropriate and shall bring his reasons for such belief to the attention of the appropriate classifying authority with a request for upgrading.
28. Downgrading and declassification-a. Automatic. Wherever practicable, the classifying official shall place a notation on classified material, except telegrams, that after a specified event or date, or upon removal of classified enclosures, the material will be downgraded or declassified.
b. Non-automatic. The appropriate classifying authority may downgrade or declassify security information when circumstances no longer warrant its retention in its original classification. When such information is downgraded or declassified the custodian of the record material, in the case of a document, or the custodian of the products or substances shall be so informed; and, when practicable the other recipients of the material shall be similarly advised.
c. Review of assigned classifications. It shall be the responsibility and obligation of every government official to keep classified security information in his custody constantly under review, and to initiate action toward downgrading or declassification as soon as conditions warrant.
PART V-DISSEMINATION OF CLASSIFIED SECURITY INFORMATION
29. General. a. No person shall be entitled to knowledge or possession of, or access to, classified security information solely by virtue of his office or position.
b. Classified security information shall not be discussed with or in the presence of authorized persons, and the latter shall not be permitted to inspect or have access to such information.
c. The head of each agency shall establish a system for controlling the dissemination of classified security information adequate to the needs of his agency.
30. Limitations on dissemination-a. Within the Executive Branch. The dissemination of classified security information shall be limited to persons whose official duties require knowledge of such information. Special measures shall be employed to limit the dissemination of "Top Secret" security information to an absolute minimum. Only that portion of "Top Secret" security information necessary to the proper planning and appropriate action of any organizational unit or individual shall be released to such unit or individual.
b. Outside the Executive Branch. Classified security information shall not be disseminated outside the Executive Branch by any person or agency having access thereto or knowledge thereof except under conditions and through channels authorized by the head of the disseminating agency, even though such person or agency may have been solely or partly responsible for its production.
c. Information originating in another agency. Except as otherwise provided by section 102 of the National Security Act of July 26, 1947, c. 343, 61 Stat. 498, as amended, 50 U.S.C. sec. 403, classified security information originating in another agency shall not be disseminated outside the receiving agency without the consent of the originating agency. Documents and material containing security information which are classified "Top Secret" and "Secret" shall not be reproduced without the consent of the originating agency.
d. Telephone conversations. Classified security information shall not be revealed over the telephone, except that the head of an agency may permit the practice of so discussing security information classified as "Restricted" which originated within his own agency.
31. Loss or subjection to compromise-Any person in the Executive Branch who has knowledge of the loss or possible subjection to compromise of classified security information shall promptly report the circumstances to a designated official of his agency, and the latter shall take appropriate action forthwith, including advice to the originating office or agency.
PART VI-RULES GOVERNING HANDLING OF CLASSIFIED SECURITY INFORMATION (INCLUDING MARKING, TRANSMISSION, STORAGE AND DESTRUCTION)
32. Marking. After determination of the classification to be assigned thereto, classified security information shall be marked in accordance with the procedures herein set forth. In order to identify classified security information and to distinguish it from non-security information, classified security material must always be clearly identified with the words "Security Information."
a. Documents-(1) Bound documents. The assigned security classification on bound documents, such as books or pamphlets, the pages of which are permanently and securely fastened together, shall be conspicuously marked or stamped on the outside of the front cover, on the title page, on the first page, on the back page and on the outside of the back cover. In each case the markings shall be applied to the top and bottom of the page or cover.
2. Unbound documents. The assigned security classification on unbound documents, such as letters, memoranda, reports, telegrams, and other similar documents, the pages of which are not permanently and securely fastened together, shall be conspicuously marked or stamped at the top and bottom of each page, in such manner that the marking will be clearly visible when the pages are clipped or stapled together.
3. Charts, maps, and drawings. Classified charts, maps, and drawings shall carry the security classification marking under the legend, title block, or scale in such manner that it will be reproduced on all copies made therefrom. Such classification shall also be marked at the top and bottom in each instance.
4. Photographs, films and recordings. Classified photographs, films, and recordings, and their containers, shall be conspicuously and appropriately marked with the assigned security classification.
b. Products or substances. The assigned security classification shall be conspicuously marked on classified products or substances, if possible; on their containers, if possible; or, if the article or container cannot be marked, written notification of such classification shall be furnished to recipients thereof.
c. Additional markings-(1) Material furnished persons not in the Executive Branch of the government. When classified security information affecting the national defense is furnished authorized persons, in or out of Federal service, other than those in the Executive Branch, the following notation, in addition to the assigned classification marking, shall whenever practicable be placed on the material, on its container, or on the written notification of its assigned classification.
This material contains information affecting the national defense of the United States within the meaning of the espionage laws, Title 18, U.S.C. Secs. 793 and 794, the transmission or revelation of which in any manner to an unauthorized person is prohibited by law.
Use of alternative marking concerning "Restricted Data" as defined by the Atomic Energy Act is authorized when appropriate.
33. Transmission-a. Preparation of classified security information for transmission-(1) Outside an agency-(a) "Top Secret" security information and "Secret security information. 1. "Top Secret" security information and "Secret" security information shall be enclosed in opaque inner and outer covers.
2. The inner cover shall be a sealed wrapper or envelop plainly marked with the assigned security classification and address.
3. The outer cover shall be sealed and addressed with no indication of the security classification.
4. There shall be attached to or enclosed in the inner cover a receipt form containing no classified security information but identifying the addressor, addressee and the document; such receipt will be signed by the proper recipient and returned to the sender.
5. Written material shall be protected from direct contact with the inner cover by a cover sheet or by folding inward.
(b) "Confidential" security information. 1. "Confidential" security information shall be prepared for transmission in the same manner as that indicated for "Top Secret" security information and "Secret" security information, except that it shall be covered by a receipt only when the sender deems it necessary.
(c) "Restricted" security information. 1. "Restricted" security information shall be transmitted in a sealed wrapper or envelope without any indication of the security classification of the contents shown thereon.
2. No receipt shall be required for "Restricted" security information.
(2) Within an agency. Preparation of classified security information for transmission within an agency shall be governed by regulations, issued by the head of the agency, insuring a degree of security equivalent to that outlined above for transmission outside an agency.
b. Transmission of classified security information-(1) "Top Secret" security information. (a) The head of each agency shall designate Top Secret Control Officers to receive, maintain registers of, and dispatch all "Top Secret" security information.
(b) The transmission of "Top Secret" security information shall be effected (1) preferably by direct contact of officials concerned, or alternatively by specifically designated personnel, by State Department diplomatic pouch, by a messenger-courier system especially created for that purpose, or by electric means in an encrypted form; or (2) in the case of information transmitted by the Federal Bureau of Investigation, such means of transmission may be used as are currently approved by the Director, Federal Bureau of Investigation, unless express reservation to the contrary is made in exceptional cases by the originating agency.
(2) "Secret" security information shall be transmitted within the continental United States by one of the means established for "Top Secret" security information, by an authorized courier, by United States registered mail, or by protected commercial express, air or surface. "Secret" security information may be transmitted outside the continental limits of the United States by one of the means established for "Top Secret" security information, by commanders or masters of vessels of United States registry, or by United States Post Office registered mail through Army, Navy or Air Force postal facilities provided that the material does not at any time pass out of United States Government control and does not pass through a foreign postal system. "Secret" security information may, however, be transmitted between United States Government and/or Canadian Government installations in continental United States, Canada and Alaska by United State sand Canadian registered mail with registered mail receipt.
(3) "Confidential" security information shall be transmitted within the United States by one of the means established for higher classifications, by ordinary mail, or by express or freight under such specific conditions as may be prescribed by the head of the department or agency concerned. Outside the continental United States, "Confidential" security information shall be transmitted in the same manner as authorized for higher security classifications.
(4) "Restricted" security information shall be transmitted within the continental United States by any means authorized for higher security classifications, or by express or freight. "Restricted" security information shall be transmitted outside the continental United States by one of the means established for higher security classifications, but registration of "Restricted" security information shall not be required when it is transmitted by Army, Navy or Air Force postal channels.
34. Physical security-a. Storage Facilities. Classified security information not in actual use by, or under direct observation of, an authorized person located in the same room shall be stored as set forth below:
(1) "Top Secret" security information shall be stored in the most secure facilities available. Normally it will be stored in a safe, a steel file cabinet, or other steel container having a three position dial-type combination lock and being of such weight, size, construction, or installation as to minimize possibility of physical theft or damage by fire or tampering. In lieu of such a container, the material may be stored in a secure room or vault approved for such use by the head of the agency and kept securely locked when
not in use. Such approval shall not be construed to relieve the custodian of any responsibility for the safety of the classified security information. If the foregoing safeguards are not available, material so classified shall be kept under surveillance of an armed guard when not in use.
(2) "Secret" and "Confidential" security information shall be stored in a manner authorized for "Top Secret" security information, or in metal file cabinets equipped with a steel lockbar and an approved three combination dial-type padlock from which the manufacturer's identification numbers have been obliterated, or in comparably secure facilities approved by the head of the agency.
(3) "Restricted" security information may be stored in a manner authorized for higher categories of classified security information, but ordinarily shall be stored in a container equipped with a reasonably secure locking device, or in any other storage facility of comparable security approved by the head of the agency.
b. Inspections. (1) It shall be the responsibility of the individual charge with the custody of classified security information to accomplish the necessary inspections within his area to insure that all procedural safeguards prescribed by these regulations are taken to protect such information at all times.
(2) In each agency individuals shall be designated to make inspections on a room or area basis to insure that all classified security information has been properly and safely stored.
c. Safe combinations. (1) Safe combinations shall be changed at least once a year; whenever a person knowing the combination is transferred from the office to which the safe is assigned; when a safe is first brought into an office; when the combination has been subjected to compromise; and at such other times as is deemed necessary
(2) Knowledge of combinations shall be limited to the minimum necessary for operating purposes.
(3) Safe combinations shall be given a security classification equivalent to that of the most highly classified security information authorized by these regulations to be contained in the safe.
35. Destruction of Classified Security Information. Types of material which may be destroyed-(1) Record material may be destroyed only in accordance with the Act of July 7, 1943, c. 192, 57 Stat. 380, as amended, 44 U.S.C. secs. 366-380.
(2) Nonrecord material may be destroyed as soon as it has served its purpose.
b. Methods of destruction. Classified record material, the destruction of which has been authorized, and classified nonrecord material shall be destroyed by the following methods under procedures established by the head of the agency:
(1) "Top Secret," "Secret" and "Confidential" security documents shall be destroyed by burning; products and substances by an equally complete method of destruction; in each case in the presence of an appropriate official. The head of an agency may authorize destruction of documents other than by burning, provided the resulting destruction is equally complete.
(2) "Restricted" security information shall be destroyed by burning, shredding or reduction to pulp, or an equally complete method of destruction.
c. Records of destruction. Appropriate records of destruction of material classified "Top Secret" and "Secret" combined with the identification "Security Information," shall be maintained in accordance with procedures established by the head of the agency.
PART VII-INTERPRETATION OF REGULATIONS BY THE ATTORNEY GENERAL
36. The Attorney General, upon request of the head of a department or agency or his duly designated representative, shall personally or thorough authorized representatives of the Department of Justice render an interpretation of these regulations in connection with any problems arising out of their administration.
HARRY S. TRUMAN
THE WHITE HOUSE,
September 24, 1951
Harry S Truman, Executive Order 10290—Prescribing Regulations Establishing Minimum Standards for the Classification, Transmission, and Handling, by Departments and Agencies of the Executive Branch, of Official Information Which Requires Safeguarding in the Interest of the Security of the United States Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/278445