by the Supreme Court as unconstitutional because of the First Amendment (see United States v. The Progressive, Brandenburg v. Ohio, New York Times Co. v. United States). , enacted in 1951, makes dissemination of secret information involving cryptography, espionage, and surveillance illegal for all people, and is thus an "official secrets act" limited to those subjects. See also DSMA-Notice, or D-Notice List of short titles Notes and references External links Troubled history of Official Secrets Act, BBC News Online Canada's Security of Information Act Christopher Moran, Classified: Secrecy and the State in Modern Britain (Cambridge: Cambridge University Press, 2012). National security policies Classified information Classified information in the United Kingdom Acts of the Parliament of the United Kingdom English criminal law