The White House, Executive Order 12356: National Security Information (Apr. 2, 1982) (full-text).
This Executive Order prescribes a uniform system for classifying, declassifying, and safeguarding national security information. The Order, implemented in 1982, continued the three-tier security classification system of confidential, secret, and top secret. It also required that agencies establish (1) controls to ensure that classified information is adequately protected when used, processed, stored, reproduced, transmitted, and destroyed and (2) procedures for the systematic and mandatory declassification of classified information.
The Order recognizes that it is essential that the public be informed concerning the activities of its Government, but that the interests of the United States and its citizens require that certain information concerning the national defense and foreign relations be protected against unauthorized disclosure. Information may not be classified under this Order unless its disclosure reasonably could be expected to cause damage to the national security.
Executive Order 12356 requires government agencies to review and declassify documents as soon as national security considerations permit. Agencies also must review documents under provisions of the Freedom of Information Act.
On April 26, 1993, a Presidential Review Directive was issued directing that the Order be reviewed, with a view toward drafting a new executive order that reflects the need to classify and safeguard national security information in the post-Cold War period.