page_title: Ultra
section_title: Role of women in Allied codebreaking
hierarchical_section_title: Ultra / Role of women in Allied codebreaking
caption_attribution_description: English: Women cryptologists of the SIS at work at w:Arlington Hall. At the right front is w:Ann Caracristi, who would later become deputy director of NSA.
context_page_description: Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School at Bletchley Park. Ultra eventually became the standard designation among the western Allies for all such intelligence. The name arose because the intelligence obtained was considered more important than that designated by the highest British security classification then used and so was regarded as being Ultra secret. Several other cryptonyms had been used for such intelligence.
  The code name Boniface was used as a cover name for Ultra. In order to ensure that the successful code-breaking did not become apparent to the Germans, British intelligence created a fictional MI6 master spy, Boniface, who controlled a fictional series of agents throughout Germany. Information obtained through code-breaking was often attributed to the human intelligence from the Boniface network. The U.S. used the codename Magic for its decrypts from Japanese sources, including the "Purple" cipher.
  Much of the German cipher traffic was encrypted on the Enigma machine.
context_section_description: After encryption systems were “broken,” there was a large volume of cryptologic work needed to recover daily key settings and keep up with changes in enemy security procedures, plus the more mundane work of processing, translating, indexing, analyzing and distributing tens of thousands of intercepted messages daily. The more successful the code breakers were, the more labor was required. Some 8,000 women worked at Bletchley Park, about three quarters of the work force. Before the attack on Pearl Harbor, the US Navy sent letters to top women's colleges seeking introductions to their best seniors; the Army soon followed suit. By the end of the war, some 7000 workers in the Army Signal Intelligence service, out of a total 10,500, were female. 
  By contrast, the Germans and Japanese had strong ideological objections to women engaging in war work. The Nazis even created a Cross of Honour of the German Mother to encourage women to stay at home and have babies.
caption: Women cryptologists at work in the U.S. Army's Arlington Hall
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