A guest post from the National Cryptologic Museum shares the story of two groundbreaking women cryptologists.

While thousands of women entered the cryptology profession during World War II, there were other pioneering female cryptologists who set the groundwork for the success of the WACs and WAVES. Two great pre-World War II women cryptologists were Agnes Meyer Driscoll and Genevieve Grotjan Feinstein. The significant strides they made for their gender paved the way for other cryptologists, male and female. These and many other women cryptologists are found in the National Security Agency’s Hall of Honor and Women in Cryptology display, “Creating the Legacy,” at the National Cryptologic Museum.  While their names are seldom found in history books, these national heroes left an indelible mark on cryptologic history and national security.

Agnes Driscoll


Cryptanalyst Agnes Driscoll who worked in the Navy’s Code and Signal Section throughout WWI. Credit: US Government courtesy of the National Cryptologic Museum

Agnes Driscoll earned a bachelor’s degree in mathematics and physics in 1911 and was proficient in English, French, German, Latin, and Japanese. She joined the Navy as a chief yeoman in 1918 and was assigned to the Code and Signal Section throughout WWI. Except for a brief time between the wars, she continued working for the Navy and broke Japanese naval systems, including their operational code known as the “Red Book,” named after the color of the two volumes’ binding and containing over 100,000 code groups.

Known as “Miss Aggie,” her skills as a cryptanalyst and ability to teach others, men and women alike, was unmatched and recognized by all in the profession. Her achievements in breaking the “Red Book” gave military commanders general knowledge of Japanese naval maneuvers and led to advances in naval aviation. Her work also revealed to American commanders Japan’s plans to exploit our weaknesses in secure communications, allowing the US to make adjustments. The Japanese continued to add new and more complicated coding systems, but Driscoll was up to the task every time, employing her amazing ability in cryptanalysis and even helping to design the Navy’s Cipher (or Communications) Machine.

While Driscoll’s greatest achievements came between the World Wars, she set the foundation for cryptanalysis in World War II and beyond.

Genevieve Grotjan


Genevieve Grotjan, who broke the challenging “Purple” Japanese code with the US Army Signals Intelligence Service. Credit: US Government courtesy of the National Cryptologic Museum

Genevieve Grotjan’s most renowned achievement came just before World War II. Although she had a degree in mathematics, she was unable to find employment as a math teacher. Instead the US Army Signals Intelligence Service (SIS) hired her and she was assigned to the “Purple” Team. This team of codebreakers was formed to break the most challenging Japanese diplomatic code to date, a code that cryptologists named “Purple.”

After 18 grueling months, the code remained unbroken. Finally, in September 1940, Grotjan made a discovery that changed the course of history. She was the first one to find the key to breaking “Purple,” a breakthrough that enabled the SIS to build an analog machine to decrypt Japanese diplomatic messages throughout WWII. Genevieve Grotjan’s contribution to the Allied victory cannot be measured, especially in the number of lives saved.

Explore World War I aerial combat, or learn how GPS receivers decode satellite signals in our Time and Navigation gallery, at our Museum in Washington, DC.

Related Topics Women Technology and Engineering War and Conflict World War I
Twitter Comments? Contact Us
You may also like WWII Women Cracking the Code