(a) Except as provided by the Atomic Energy Act of 1954, as amended, (42 U.S.C. 2011) or the National Security Act of 1947, as amended, (50 U.S.C. 401) Executive Order 12958 provides the only basis for classifying information. Information which meets the test for classification may be classified in one of the following three designations:

(1) Top Secret. This classification shall be applied only to information the unauthorized disclosure of which reasonably could be expected to cause exceptionally grave damage to the national security that the original classification authority is able to identify or describe.

(2) Secret. This classification shall be applied only to information the unauthorized disclosure of which reasonably could be expected to cause serious damage to the national security that the original classification authority is able to identify or describe.

(3) Confidential. This classification shall be applied only to information the unauthorized disclosure of which reasonably could be expected to cause damage to the national security that the original classification authority is able to identify or describe.

(b) If there is significant doubt about the need to classify information, it shall not be classified. If there is significant doubt about the appropriate level of classification, it shall be classified at the lower level.