Women who served as code breakers for the US during WW II
U.S. Army Signals Intelligence Service cryptologists, mostly women, at work at Arlington Hall circa 1943
The Code Girls or World War II Code Girls is a nickname for the more than 10,000 women who served as cryptographers (code makers) and cryptanalysts (code breakers) for the United States Military during World War II, working in secrecy to break German and Japanese codes.[1]
These women were a crucial part of the war and broke numerous codes that were of significant importance to the Allied Forces and helped them to win and shorten the Second World War.
Recruitment
In the months prior to the Japanese attack on Pearl Harbor, the United States Military began to recruit women to work for their various branches, as the men who previously occupied these positions were deployed overseas to fight in the war.[2]
Many of the recruited women were hired to work as cryptographers and cryptanalysts by the United States Navy. These women had to be native to the United States, as to make sure that they had no ties to foreign countries.[2] The government sought after young females who pioneered the STEM field and excelled in mathematics and world languages—often young college students and teachers with a driving motivation.[3] After the attack, the Navy's recruitment activities and advertisements increased dramatically as the United States' joined the Allied Forces to fight Axis powers during World War II.[2]
During the recruitment process, the women were asked if they liked crossword puzzles and if they were engaged or wanted to be married. Those who answered 'yes' and 'no', respectively, were moved forward in the hiring process. The military were looking for women that were willing to relocate and had little to no ties to their current lifestyle.[4] Candidates were invited to secret meetings where they were offered the opportunity to take a code-breaking training course and were sworn to secrecy- exposing their work was considered treason and could have been punishable by death. Those who passed the course were invited to Washington, D.C. after college graduation to join the Navy as civilian employees.[2]
The Army also began recruiting women code breakers around this time. Army officials met with representatives from women's colleges at the Mayflower Hotel in hopes of recruiting their top students before the Navy was able to do so, and in May of 1942, the female civilian code breakers, were accepted into the Women's Army Auxiliary Corps, and thus into Military Service .[5]
Due to the nature of secrecy of the female code-breakers of World War II and the "loose lips sink ships" propaganda and mentality during that time, a significant amount of their work and recruitment process remains a mystery, and without an existing record of a roster of all of the Code Girls, it is almost impossible to track down all of these individuals and get all of the details of their recruitment experience.[1]
Code-breaking
Women at Arlington Hall operate a machine, right, that unscrambles messages in the Japanese ""Purple" cipher. The machine's existence was one of the most closely guarded secrets of the war.
The Army also quickly outgrew its Washington, D.C. office and added a second location at Arlington Hall Junior College for Women.[4] By 1945, 70 percent of the Army's code-breaking team was female.[2]
Among their duties, the women operated code-breaking machines, analyzed and broke enemy codes, built libraries of resources on enemy operations, intercepted radio signals, and tested the security of American codes.[2] During their preparation, code girls were trained by the government in top-secret coding classes.[3] In these classes, women learned cryptography, making codes, and cryptanalysis, breaking codes.[1] The work they did in the Navy was highly classified—the punishment for sharing their work being punishable by death.[3]
During each month of 1944, code breakers intercepted about 30,000 Japanese Navy water-transport messages which led to the sinking of nearly all Japanese supply ships heading to the Philippines or South Pacific. Prior to D-Day, they shared false information and radio messages to intentionally mislead the Germans about the Allied Forces' landing location.[7]
A major accomplishment by female cryptographers was breaking the Purple Cipher. An intricate and improved version of the German Enigma Machine was created by the Japanese government—dubbed the "Purple" Enigma.[8] The complexity of this machine was revolutionary, but code girl, Genevieve Grotjan, along with her team broke the Japanese codes.[8] The result of their work allowed the U.S. naval forces to plan and execute the Battle of Midway, ultimately changing the course of the Pacific Theater of World War II.[8]
When asked publicly about their highly sensitive work, the women were told to reply that they 'sharpened pencils and emptied wastebaskets'. Reportedly, their cover story was never challenged.[2][4]
Gender Inequality
Female cryptographers in World War II faced many discriminatory challenges in the work force. These recruited women acquiring adept skills in math, science, and foreign languages, were to remain dutiful and patriotic with no expectation of public credit for their concealed intelligence work.[5] Many people (mainly men) considered women better suited for code-breaking work. Inferring the oppressive belief that women were greater equipped for dull work and thus assigned work requiring close attention to details rather than challenging genius commissions. That was considered men's work at the time. Due to these injustices women struck back, but this led to the public believing women were gossipers and complainers. However society believed women were also less problematic with drinking and bragging. In terms of sexual behavior, women were seen less of a security risk than men. [5]
In public, the women were authorized to keep their jobs confidential, and substitute their work as secretaries or did menial jobs, completing tasks such as sharpening pencils and taking out the trash. If a stranger were to show suspicious interest about their work, some groups would use certain signals in bars to alert the other women.[5] For example if a group member ordered a Vodka Collins then the Code Girls knew to dismiss themselves to the restroom and flee the area. Other women improvised their answers and strategically sat on the laps of commanding officers and soldiers. As young American women it was effortless to convince curious strangers that they did menial work or existed only as a plaything for the men they worked with. [5]
For more than 70 years women in this generation did not expect nor receive recognition for achievement in public life. Their efforts were completely hidden and only mentioned in passing, with no historical record, interviews, or first-person memoirs afterwards. Now their story is being told in various sources such as the articles and books of Liza Mundy, “including the National Archives in College Park, Maryland, and other archival repositories along with declassification requests and interviews with living code breakers” [5] Years later some Code Girls feel reluctant to reveal certain information outside of the Code-breaking compound.[5]
After World War II
The Code Girls of World War II laid out important foundations and pioneered the work that would become part of modern-day cybersecurity and communication agencies. They created pathways to clandestine eavesdropping operations, and after the end of the war, the Navy and Army secret cryptography operations were merged to create what it is now known as the National Security Agency.[2]
Many of the women were kicked out of the Military and pushed out of the technological workforce after the war ended, as the deployed soldiers returned from war and settled back into their previous jobs- with only a few continuing to work for the National Security agency and other roles within the military. These women were all sworn to secrecy and their work and contributions went silent for years, which led to many of their accomplishments to be forgotten or claimed by their male counterparts.[9]
Impact and accomplishments
Additionally to the Army’s code breaking operation, there was an African American group unit (implemented by Eleanor Roosevelt) that helped with the enciphered communications of certain companies, and to get better insight of who was collaborating with dictators such as Mitsubishi and Hitler. Women such as Agnes Meyer Driscoll, aided in unraveling the Japanese navy fleet codes during the 1920s and 1930s.
Another significant cryptanalyst named Elizabeth Smith Friedman was the first to discover the US government’s codebreaking bureau in 1916, where she worked for Riverbank at an unconventional Illinois estate. During prohibition, she deciphered the codes of which businesses were smuggling alcoholic beverages, also known as rum running. In September 1940, due to Genevieve Grotjan’s key expertise, the Allies were able to get information on the Japanese diplomats’ communications throughout World War II. Her decrypting assisted in monitoring the enciphering machines used by Hiroshi Oshima, Japanese Ambassador to Nazi Germany, who was close to Adolf Hitler and other Nazi political and military leaders. He got much detailed information from the Nazis, and was given access to their military installations - which he transmitted to Japan, not realizing that the Americans were reading his transmissions which were a major source of information.
The navy and army were all competing for the women’s skills after recognizing all of their efforts made in the World War. Specifically, Ada Comstock urged for the Navy to train the undergraduates in cryptanalysis, realizing how the country lacked a demand of educated women after the surprise attack at Pearl Harbor. More women were being enlisted in the workforce, especially to the WAAC recruiting station, where they needed to pass background checks to be in the code breaking service. At Arlington Hall (which became the headquarters of the United States Army Signal Intelligence Service), Ann Caracristi went against master Japanese cryptanalysts and solved many message addresses which helped the military intelligence locate many of the Japanese troops. Japanese ships were sunk as a result of the messages given to Dot Braden and other women who deciphered naval codes along the major oceans.
The Japanese fleet code called JN-25 was used by these women who created the cryptoanalytic assembly line, and aided in shooting down Isoroku Yamamoto's plane. All of the machines that targeted and attacked the German Enigma ciphers were managed by women, additionally they tracked the locations of Allied convoys and U-boats. In order to destroy the German naval Enigma ciphers, women assisted in building one hundred "bombe" machines in a classified building located in the National Cash Register Company. JAH, which was an all purpose code that contained important material such as speeches, orders and memos was handled by Virginia Dare Aderholdt. She was able to know when Japan evacuated from southern China and track all of Naotake Sato's endeavors.[2]
Notable WW II era women cryptologists
Notable women who contributed to the U.S. cryptologic effort during the World War II era include:
Bletchley Park is an English country house and estate in Bletchley, Milton Keynes (Buckinghamshire), that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years following 1883 for the financier and politician Herbert Leon in the Victorian Gothic, Tudor and Dutch Baroque styles, on the site of older buildings of the same name.
Cryptanalysis refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown.
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 (GC&CS) 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.
In the history of cryptography, the "System 97 Typewriter for European Characters" or "Type B Cipher Machine", codenamed Purple by the United States, was an encryption machine used by the Japanese Foreign Office from February 1939 to the end of World War II. The machine was an electromechanical device that used stepping-switches to encrypt the most sensitive diplomatic traffic. All messages were written in the 26-letter English alphabet, which was commonly used for telegraphy. Any Japanese text had to be transliterated or coded. The 26-letters were separated using a plug board into two groups, of six and twenty letters respectively. The letters in the sixes group were scrambled using a 6 × 25 substitution table, while letters in the twenties group were more thoroughly scrambled using three successive 20 × 25 substitution tables.
William Frederick Friedman was a US Army cryptographer who ran the research division of the Army's Signal Intelligence Service (SIS) in the 1930s, and parts of its follow-on services into the 1950s. In 1940, subordinates of his led by Frank Rowlett broke Japan's PURPLE cipher, thus disclosing Japanese diplomatic secrets before America's entrance into World War II.
Books on cryptography have been published sporadically and with highly variable quality for a long time. This is despite the tempting, though superficial, paradox that secrecy is of the essence in sending confidential messages — see Kerckhoffs' principle.
Elizebeth Smith Friedman was an American cryptanalyst and author who deciphered enemy codes in both World Wars and helped to solve international smuggling cases during Prohibition. Over the course of her career, she worked for the United States Treasury, Coast Guard, Navy and Army, and the International Monetary Fund. She has been called "America's first female cryptanalyst".
Agnes Meyer Driscoll, known as "Miss Aggie" or "Madame X'", was an American cryptanalyst during both World War I and World War II and was known as "the first lady of naval cryptology."
Cryptography, the use of codes and ciphers to protect secrets, began thousands of years ago. Until recent decades, it has been the story of what might be called classical cryptography — that is, of methods of encryption that use pen and paper, or perhaps simple mechanical aids. In the early 20th century, the invention of complex mechanical and electromechanical machines, such as the Enigma rotor machine, provided more sophisticated and efficient means of encryption; and the subsequent introduction of electronics and computing has allowed elaborate schemes of still greater complexity, most of which are entirely unsuited to pen and paper.
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The Signal Intelligence Service (SIS) was the United States Army codebreaking division through World War II. It was founded in 1930 to compile codes for the Army. It was renamed the Signal Security Agency in 1943, and in September 1945, became the Army Security Agency. For most of the war it was headquartered at Arlington Hall, on Arlington Boulevard in Arlington, Virginia, across the Potomac River from Washington (D.C.). During World War II, it became known as the Army Security Agency, and its resources were reassigned to the newly established National Security Agency (NSA).
With the rise of easily-intercepted wireless telegraphy, codes and ciphers were used extensively in World War I. The decoding by British Naval intelligence of the Zimmermann telegram helped bring the United States into the war.
Ann Zeilinger Caracristi was an American cryptanalyst, former Deputy Director of the National Security Agency, where she served at various positions over a 40-year career. She served as a member of the Secretary of Defense Joint Security Commission and President's Foreign Intelligence Advisory Board. She became the first woman at NSA to be promoted to GS-18 rank, in 1975, when she became the Chief of Research and Operations.
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Genevieve Marie Grotjan Feinstein was an American mathematician and cryptanalyst. She worked for the Signals Intelligence Service throughout World War II, during which time she played an important role in deciphering the Japanese cryptography machine Purple, and later worked on the Cold War-era Venona project.
Liza Mundy is an American journalist, non-fiction writer, and fellow at New America Foundation.
Wilma Zimmerman Davis was an early American codebreaker during World War II. She was a leading national cryptanalyst before and during World War II and the Vietnam War. She graduated with a degree in Mathematics from Bethany College and successfully completed navy correspondence course in cryptology. She began her career as a leading cryptanalyst which spanned over 30 years in the United States Army Signal Intelligence Service (SIS), a predecessor of the National Security Agency (NSA) in the 1930s. She was hired by William Friedman, who was a US cryptographer in the Army and led the research division of the Army’s Signal Intelligence in the 1930s. Wilma Davis worked as a cryptanalyst on the Italian, Japanese, Chinese, Vietnamese, and Russian problems. She also worked on the VENONA project.
Mary Caroline "Polly" Hughes Budenbach was an American cryptanalyst. She won the Federal Woman's Award in 1969, and was posthumously inducted into the NSA Hall of Honor in 2017.
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