The first world war showed the importance of cryptography on the battlefield, and the danger of weak encryption. The second world war became a defining moment in the history of cryptography and placed it squarely at the center of military and political strategy from that time to the present day.

The Enigma machine was developed by a German Arthur Scherbius in 1918 and was patented in 1919. It was marketed with portability and confidentiality as it sales features, but it had a lack of commercial success. When Germany discovered that they had lost WW I as a result of their cipher having been cracked by the British, despite the high cost, the machine was adopted by the German Navy in 1926, the Army in 1928 and the Air Force in 1935; also it was introduced into service with other sections of the German government.