NSA has released under FOIA nine crypto papers in response to a November 2000 request for information on non-secret encryption and JH Ellis, British cryptographer long at CESG. Non-secret encryption preceded the invention of public key crypto. Three of the papers were formerly classified as Top Secret Codeword, one Secret (by JH Ellis, 1977) and others Confidential (Clifford Cocks, 1998) and FOUO. http://cryptome.org/nsa-nse/nsa-nse-01.htm