NSA Special Research Histories available for download

The following recently declassified Special Research Histories can be downloaded from the NSA website:

SRH-361 ‘History of the Signal Security Agency Volume Two The General Cryptanalytic Problems’

SRH-364 ‘History of the Signal Security Agency Volume One 1939 – 1945’

SRH-361 is very interesting since it has details not only on US cryptanalysis of Japanese, Italian and German systems but also on the codes of neutral and Allied countries (China, Poland, Greece, Turkey, Czechoslovakia, etc).