The Untold History of The American Women Code Breakers of World War II

Women played a crucial part in World World II. One of the big ways they made a difference was when a group of more than ten thousand women served as cryptographers, also called Code Girls. The women chosen worked at military-operated facilities such as Arlington Farms in Virginia, Naval Shipyards, or WAVE headquarters in Washington, D.C. They worked to end the war in silence, cracking and creating codes, and were silenced to secrecy.
The U.S. Military Quietly Recruited Women From Elite Colleges And Universities
All over the world, groups of college-educated women were personally recruited from campuses, selected at the recommendation of their alma mater. Some women began seeking out United States Navy WAVES or United States Army WAC recruiters after their creation in 1942.

They were recruited after graduation or were trained at women's colleges all over the country. They recruited women with specific skills and degrees in language, science, music, and math. In addition, the women needed to exude a loyal disposition and possess high integrity.
The Women Recruited Had To Take Secret Courses
The women that were chosen were issued manila envelopes that contained a brief introduction to the arcane history of codes and ciphers. In addition, they received numbered problem sets for them to complete every week.

In 1942, the first wave of women that were recruited finished their secret courses and turned in their final problem sets. However, only about half of the women that took the secret courses passed and were sent to the Washington, D.C. headquarters.
Virginia Dare Aderholdt
During World War II, Virginia Dare Aderholdt was an Arlington Hall cryptanalyst and Japanese translator. She decrypted the intercepted Japanese surrender message on August 14, 1945. She mostly decrypted the messages in an older diplomatic code, JAH.

Because she was fluent in Japanese, she could decrypt and translate simultaneously. She is most known for decrypting and translating the message saying that the Japanese were surrendering.
The Women That Were Recruited Were Smart And Resourceful
The women that were recruited all had very different backgrounds, but they also had a handful of qualities in common. All of the women were smart and resourceful and were great with math, science, or foreign languages, often all three.

In addition, the women strived to get as much schooling as circumstances would allow at a time when women received very little encouragement or reward for doing so. The women were also adventurous, willing, dutiful, patriotic, and didn't expect any public credit for their work.
Ann Z. Caracristi
After graduation, Ann Z. Caracristi was recruited by the Army to work as a code breaker. She was recommended by the Dean of Russell Sage, and she worked on IBM machines. She started with sorting paper but worked her way up through the ranks and was sent to Washington, D.C.

Later, she worked as a member of the Secretary of Defense Joint Security Commission and the President's Foreign Intelligence Advisory Board. In addition, Ann became the first woman at NSA to be promoted to GS-18 rank and became the Chief of Research and Operations.
First Recruits Reported To Navy Headquarters In Washington, D.C.
The first code breaker recruits reported to Navy headquarters in Washington, D.C. During the war, women made up an astonishing eighty percent of the ranks. In addition, the Army also made use of the female cryptanalysts but had them stationed at Arlington Hall in Northern Virginia.

However, the offices became overcrowded and less than desirable to work at. So, in 1943, the Navy expanded its operations by using the original location of Mount Vernon College for Women as the Naval Communications Annex.
A Second Location Was Added At Arlington Hall Junior College For Women
Arlington Hall was a junior college for females and a boarding school for high school and junior college students from 1927 until 1942. However, in 1942, the United States Government took over Arlington Hall as their new location for cryptanalysis work and military intelligence.

It became the central hub for the Women's Army Corps, where more than one thousand women worked during World War II. After the war ended, the National Security Agency remained there for a few years and today is a federal installation and a training center.
Agnes Meyer Driscoll
Agnes Meyer Driscoll was a brilliant young teacher who studied mathematics, music, physics, and foreign languages. She was one of the first women to enlist in the war and started as a stenographer.

However, she was soon assigned to the Navy's postal and censorship office and was transferred to the code and signal section. Agnes became one of the greatest cryptanalysts of all time but was discharged after the war ended. She was hired back by the Navy as a civilian.
Women Were Told To Say They ‘Sharpened Pencils And Emptied Wastebaskets’
The women's work was to be kept entirely secret, and they were told that if they committed treason, they would suffer the full consequences. The women were told to say they emptied trash cans and sharpened pencils if they were asked about their jobs.

A group of women all agreed that if anyone ordered a vodka Collins when they were out at a bar together in Washington, that would be their signal that someone was showing too much curiosity about their work. They would all disperse to the ladies' room and then leave. Many thought the women were nothing more than secretaries.
Bletchley Park Was The Most Well-Known Site
Bletchley Park was the main site for British cryptanalysis during World War II and housed the Government Code and Cypher School. It is famous for its impact on the war and for the work that was performed there.

The Code and Cypher School penetrated the secret communications of the Axis Powers, especially the German Enigma and Lorenz ciphers. Several of the full-fledged female codebreakers went on to have very successful careers in cryptanalysis.
Helen Nibouar
Helen Nibouar was a cryptographer and part of the select group who first worked on the SIGBA cipher device during World War II. She was recruited by a woman who encouraged her to give cryptography a try and trained at Morrison Field.

There she met Marion Johnson, and the two worked together on the SIGBA cipher device, used to secure troop movements and other sensitive material. Helen later worked as an instructor, teaching cryptography to military personnel.
Genevieve Grotjan Feinstein
Genevieve Grotjan Feinstein was a mathematician and cryptanalyst who worked for the Signals Intelligence Service during World War II. She played an important role in decoding the Japanese cryptography machine Purple.

She played a key role in cracking the cipher, which enabled the construction of an equivalent machine by the SIS. It enabled the interception of almost all messages exchanged between the Japanese government and its embassies in foreign countries.
In 1942, President Franklin Roosevelt Signed The Navy Women’s Reserve Act
The Navy accepted a large number of enlisted women and the first female commissioned officers who would supervise them. In 1942, President Franklin Roosevelt signed the Navy Women's Reserve Act into law, which created what was commonly known as the WAVES, or Women Accepted for Volunteer Emergency Service.

It was a division of the United States Navy that was created during World War II in order to free up men for sea duty. Before the act was signed into law, women were not considered members of the military.
The Bombe Machine
The Bombe was an electromechanical device used during World War II. It was used by British cryptologists to help decipher German Enigma-machine-encrypted secret messages.

Later, the US Army and US Navy produced their own machines to do the same thing. The machine was designed to discover some of the daily settings of the Enigma machines on the various German military networks.
Margaret Crosby
Margaret Crosby was an archaeologist and historian and graduated from Bryn Mawr College in 1922. During the Second World War, she joined the Office of Strategic Services and worked as a cryptographer for the OSS' Greek Desk.

Margaret deciphered reports and materials for the Allied Forces and accompanied Gerard Else when he led the move from Cairo to Caserta. As a result, she moved to Athens with the Greek Desk in 1944 and worked there until 1945.
Not All Of The Messages They Decrypted Were About War
While the majority of the messages that the women's code breakers decoded were about the war, there were always some that were more personal. There were messages about birthdays, deaths, and birth notices. Parsons felt like she got to know many of the men and their families in a way that humanized them.

She stated, "This one man was so happy because finally, he and his wife had a little boy, and it wasn't a week later that his submarine was sunk. I felt so bad about that because he'll never know his father."
Secret Unit Of African American Women Code Breakers
During World War II, there was a unit put together of African American women who secretly worked as code breakers in Arlington, the massive intelligence operation. The Arlington Hall Station was unusual for the time in that up to fifteen percent of its workforce was Black.

However, because of segregation, even people working at the station weren't aware of the special unit, and most of the identities of Arlington's Black code breakers remain unknown.
The Women Code Breakers Didn’t Receive Any Credit
The women working as code breakers during WWII did not expect any public credit for the important work they did. Over the last hundred years, women have worked in code-breaking but never received any recognition.

The women didn't write the history afterward or first-person memoirs, which kept their efforts completely hidden for more than seventy years. However, their contributions are now beginning to be recognized due to forgotten papers and interviews.
Mavis Batey
Mavis Batey was one of the leading codebreakers during World War II at Bletchley Park. She worked as an assistant to Dilly Knox and was involved in the decryption effort before the Battle of Matapan.

Mavis developed a successful technique that later decoded a message that led to the destruction by an Allied force of much of the Italian naval force off Cape Matapan. In addition, she was awarded the Veitch Memorial Medal in 1985.
It Was Women Who Helped Found Venona
A group of women code breakers helped identify those who passed American and Allied secrets to the Soviet Union during and after World War II. Their work unveiled such infamous spies as the British intelligence officer Kim Philby, the German-born scientist Klaus Fuchs, the British diplomat Donald Maclean, and several others.

Their work was so classified that even President Harry Truman didn't even know about it. The women involved were Mildred Hayes, Jo Miller Deafenbaugh, Gloria Forbes, Carrie Berry, Joan Malone Callahan, and Gene Grabeel.
Women Built Libraries Of Speeches
Female code breakers were instrumental at every stage of World War II. In Washington, they ran complex office machines that were converted for code-breaking purposes.

In addition, they built libraries of public speeches, lists of ship names and enemy commanders, and shipping inventories, which helped break messages. The women worked as translators and were put in charge of systems such as weather codes, which were crucial when major systems went dark and could not be read.
Elizebeth Smith Friedman
Elizebeth Smith Friedman was an expert cryptanalyst who deciphered many enemy codes during both World Wars. In addition, she helped solve international smuggling cases during Prohibition. Friedman was often called 'America's first female cryptanalyst,' as a woman with a sharp mind and nerves of steel.

During World War II, she helped break up a Nazi spy ring across South America, but until recently, most Americans had never heard of her. In fact, a man named J. Edgar Hoover took credit for Friedman's success.
Women Tested America’s Own Codes To Make Sure They Were Secure
During World War II, women codebreakers served several roles. They listened for coded radio messages from other countries and tested American codes to ensure enemies couldn't break them.

In addition, they collected names of enemy ships and commanders that could possibly be in a coded message, which could help them break the code. The women looked for patterns, such as where and when messages were sent, which could be clues about troops' movements.
Only Women Code Breakers Were Permitted To Go Overseas
During World War II, the Navy did not permit its women to serve overseas, even though several of the women wanted to. There were several who went to Hawaii, and the Army did allow its code-breaking women into the war theater.

Some Army women were sent to Australia and the Pacific islands such as New Guinea. In addition, some women moved with General Douglas MacArthur when he occupied Tokyo after the war.
“Dummy Traffic” Or Fake Radio
Some of the women code breakers helped create 'dummy traffic,' also called fake radio. They sent fake radio signals that helped fool the Germans into believing the D-Day invasion would take place in Norway or the Pas-de-Calais region of France instead of the beaches of Normandy.

The women were able to design dummy encrypted radio traffic so authentic that it tricked the Nazis. "Fake radio traffic fooled the Germans into thinking we had a completely fictitious landing force that was poised to invade Calais. We'd even named it: it was called the First U.S. Army Group. It was supposed to be led by General George Patton." ------ Mundy.
Margaret Rock
Margaret Rock was recruited to Bletchley Park after she had impressed Dillwyn Knox, head of Intelligence Service at the Government Code and Cypher School. He wrote about her, "Miss Rock is entirely in the wrong grade. She is actually fourth or fifth best of the whole Enigma staff and quite as useful as some of the professors. I recommend that she should be put on the highest possible salary for anyone of her seniority."

Margaret received the top salary for a woman at that time, a promotion to Linguist, and her work is recorded in the official history of the Abwehr code-breaking operation.
Women Were Considered Better Suited For Code Breaking Work
During World War II, women were considered better suited for code-breaking work because it was thought they were better equipped for tedious work that required close attention to detail rather than leaps of genius. Men were seen as more brilliant but also more impatient and erratic.

So the women were given the repetitive work so that the men could take over when things got interesting and hard. However, there have been female geniuses whose contributions are as important as those of men all along.
They Laid The Groundwork For The Field Of Cybersecurity
The women listening in on enemy conversations provided a verbatim, real-time way to know what the enemy was thinking, doing, arguing about, worrying over, and planning.

Codebreaking provided information on troop movements, shipping itineraries, strategy, battlefield casualties, political alliances, pending attacks, and supply needs. The women advanced what is known as signals intelligence, which laid the groundwork for the field of cybersecurity, the modern computing industry.
Women Played A Central Role In Shortening The War
Women played a central and important role in significantly shortening the war. Their work was crucial to Allied success in defeating Japan and without it, the war could have continued for years.

The Joint Committee stated, "The Signals Intelligence was some of the finest intelligence available in our history. It contributed enormously to the defeat of the enemy, greatly shortening the war and saving many thousands of lives."
They Helped To Destroy Almost Every Supply Ship And Convoy
Thanks to the intelligence revealed by the WAVES of OP-20-G, ninety-five German U-boats were either sunk or captured by the end of World War II. For example, it was discovered that German U-boats were planning on sinking the ship, Queen Mary.

Elizebeth Friedman's discovery allowed the Queen Mary ship to evade the U-boats and saved more than eight thousand soldiers who were on board. It prolonged the severing of supply lines, which was actually what killed the most Japanese troops during the war.
Joan Clarke
Joan Clarke was a codebreaker, and her work during the war saved countless lives. In addition, her work was formidable enough to command the respect of some of the greatest minds of the twentieth century. Clarke was the only woman to work as part of the quest to crack German Enigma ciphers.

She rose to deputy head of Hut 6 and was the longest-serving member, where her task was to break the ciphers quickly. The messages that Clarke decoded resulted in some military action being taken almost immediately.
The Women Learned Tricks
Codebreaking required a strong understanding of math since many ciphers replaced letters with numbers and hide the message with equations. The women needed good memory, persistence, and patience, and they learned plenty of tricks.

For example, they would look for short phrases that sometimes marked the start of the coded notes, like "begin message here." They studied long strings of letters and numbers while looking for patterns that might reveal a message hidden in sentences that looked like nonsense. All of these tricks helped them figure out the rest of the code.
The Women Were Treated Poorly
Even though women were doing very important work during World War II, they were sometimes treated poorly. For instance, the women codebreakers were doing the same work as men but were paid much less, and some military men treated the women poorly because they didn't think the women were important.

Mundy stated, "The women also had to constantly work against public fears of their independence. As the number of military women expanded, rumors spread that they were 'prostitutes in uniform,' and were just there to 'service the men.'" The image above shows women that worked as code breakers at Bletchley Park together again at a reunion.
Many Women Were Kicked Out Of The Military After The War Ended
Thousands of women served during World War II as codebreakers and, in fact, played a crucial role in ending the war and saving lives. However, most were kicked out of the military after the war ended.

Sadly, it was decades before they were recognized for their achievements. Women's employment was only encouraged as long as the war was on, but when it ended, federal and civilian policies replaced women workers with men. The photo shows just a few of the women who worked as code breakers during WWII.
Every Woman Was Asked Two Questions Before They Could Be Considered
In 1941, a handful of letters began showing up in student mailboxes at America's top women's colleges. Of course, the messages were cryptic and brief and required the women to decode them.

The letter invited the mystified recipients to private interviews where they would be asked only a couple of cryptic questions. The women were all asked: Did they like crossword puzzles? and were they engaged to be married? The correct answers were yes and no.
The Women Mastered The Vigenere Square
The Vigenere square saw rapid development in cryptography in order to secure messages from one's enemy. It helped code-breakers create the Enigma machine during World War II. The code girl students learned the Vigenere square as a method of disguising letters dating from the Renaissance.

They had to learn about the mathematical properties of language, letter combinations, and various cipher alphabets. The photo shows just one of the decoding machines used during WWII.
The Playfair Ciphers
Cryptanalysis of the Lorenz cipher, also called the Playfair cipher, was the process that enabled the British to read high-level German army messages during World War II. They decoded several communications between the OKW, the German High Command in Berlin, and their army commands throughout occupied France.

The communications were intercepted non-Morse radio transmissions that had been enciphered by the Lorenz SZ teleprinter rotor stream cipher attachments. This all became an important source of intelligence and contributed greatly to Allied victory.
The Wheatstone Ciphers
The Wheatstone's cipher was invented by Decius Wadsworth, a Colonel in the United States Army. The system involved a set of two disks, one inside the other, and the outer disk had twenty-six letters of the alphabet and the numbers two through eight.

The inner disk just had the twenty-six letters. Originally called Wadsworth's cipher, it was continuously improved upon and used until the end of World War II.
Other Women Worked As Y-Station Listeners And Messengers
Some of the women decoders were also Y Listeners and messengers. They risked their lives to intercept and gather enemy communications, and the 'Y Service' was an elite group of WRENS at Bletchley Park during World War II.

Their work was a closely guarded secret. The women intercepted enemy communications to gather the Nazi Enigma machine codes for the British code-breakers to solve. The information they gathered was crucial to staying one step ahead of the enemy.
The Women Were Not Able To Officially Join And Serve Until 1942
Originally, the women codebreakers that were brought in by the Army and Navy were still considered civilians. They weren't allowed to officially join and serve until 1942, but even then, there were considerable disparities.

They received unequal pay, benefits, and respect, despite the obvious need for their service and the value they held. However, the women that were recruited knew that they wouldn't be acknowledged for their success. The photo above is the British forces' intelligence center at Bletchley Park, Buckinghamshire.
The Purple Machine
The Type B Cipher Machine was codenamed Purple by the United States, and it was an encryption machine that the Japanese Foreign Office used. It was an electromechanical machine that used stepping-switched to encrypt the most sensitive diplomatic traffic.

Codebreakers worked on purple machines in 1944 in order to help break the cipher used to send secret Japanese messages during World War II.
Many Took What They Learned To Their Graves
Women codebreakers had a difficult job, and on top of that, they couldn't talk about their jobs, and most lived in cramped conditions. They worked in an environment of large and clashing male egos, and their work was simply dismissed.

In fact, men would take credit for the women's accomplishments, but there was nothing the women could do. They were sworn to secrecy, and most took what they did and accomplished during World War II to their graves. There were a select few that eventually talked and gave interviews. This image shows Public Record Office worker Philippa Wadsworth looking at documents that were released to the public for the first time.
The Enigma
The Enigma machine is a cipher device that was used to protect diplomatic, commercial, and military communication. It was used extensively during World War II and was considered so secure that it was used to encipher the most top-secret messages.

It worked by one person entering the text on the Enigma's keyboard while another person wrote down which of the twenty-six lights above the keyboard illuminated when the keys were pressed. Several stated that the flow of Ultra communications, intelligence from the decryption of Enigma, and other machines shortened the war substantially.
William Coffee Recruited The African American Women
William Coffee was an African American man who supervised and recruited African American women for a new analyst unit. He ended up recruiting more than one hundred African American scholars, analysts, and linguists for the agency.

The secret unit focused on the task of breaking non-governmental commercial codes from various foreign countries. The women struggled against the racism of the era as their unit was kept segregated; they were paid less and were hired at lower positions.
Hut 6
Hut 6 was a building comprised of exclusively female code-breakers who would receive Enigma keys every day and would have to determine if the messages in any way resembled German. It was stated that the working conditions inside were horrible, with poor lighting, heating, and a lack of proper ventilation.

One of the women that worked at Hut 6 was Jane Fawcett, and she was able to decode a message regarding the position of the Bismarck and its destination in France. It was the first huge victory for Bletchley Park and the code-breakers.
Dorothy Braden Bruce Was One Of The First To Learn That WWII Was Over
Dorothy Braden was a top-secret code breaker during World War II. Her unit worked to disclose the locations of Japanese ships in the Pacific, protect the lives of American service members, and identify and intercept enemy supply movements.

She was sent to work in the nation's capital at Arlington Hall, where she helped pinpoint and sink almost every supply ship heading to the Philippines or the South Pacific. Dorothy knew that the war was over even before President Franklin D. Roosevelt knew.
The Colossus Computer
The Colossus was the code-breaking electronic computer used at Bletchley and was designed by Tommy Flowers. It was used for radio transmissions and was liable to be overheard and possibly deciphered.

At Bletchley Park, their challenge was to decipher a system that required the receiving machine to be set so that the pattern of restoration kept in step with the pattern at the transmitting end. After the women found the pattern, they had to try millions of possibilities to break into the cipher, which is what the Colossus was designed to do. The photo shows the control panels of Colossus, the world's first electronic programmable computer, at Bletchley Park.
Bletchley Park Girls
The Bletchley Girls consisted of many women code breakers, but three of them are shown in the photo below: Rozanne Colchester, Pamela Rose, and Ruth Bourne. Rozanne was fluent in Italian, which was helpful in the air force section, where she decoded hand-encrypted messages.

Pamela Rose knew German and worked in Bletchley's naval indexing section, where she cross-referenced, logged, and filed intercepted messages. Finally, Ruth Bourne trained to be a Bombe operator and worked on one of the codebreaking machines at RAF Eastcote.
WAVES Of OP-20-G
OP-20-G was 'Office of Chief Of Naval Operations' and was the United States Navy's signals intelligence and cryptanalysis group during World War II. The mission was to decrypt, intercept, and analyze communications from the German, Japanese, and Italian navies.

It also copied the diplomatic messages of many foreign governments. The contributions of the many women code breakers employed by OP-20-G during World War II were critical in helping to win the Secret War. The photo above shows a code breaker using one of the decoding machines.