49 CFR § 806.1 - General policy.
(a) The interests of the United States and its citizens are best served by making information regarding the affairs of Government readily available to the public. This concept of an informed citizenry is reflected in the Freedom of Information Act and in the current public information policies of the executive branch.
(b) Within the Federal Government there is some official information and material which, because it bears directly on the effectiveness of our national defense and the conduct of our foreign relations, must be subject to some constraints for the security of our Nation and the safety of our people and our allies. To protect against actions hostile to the United States, of both an overt and covert nature, it is essential that such official information and material be given only limited dissemination.