Honoring Genevieve Grotjan Feinstein, Cryptanalyst

Genevieve Grotjan Feinstein was known for her flashes of insight that led to successes of the entire cryptanalytic team. In 1940, Ms. Grotjan made a breakthrough against the Japanese diplomatic system known as “Purple.”

She found consistent relationships between the ciphertext and the plaintext in the messages. Her work was critical to the success of the team that solved Purple. In 1944, while working on the Russian diplomatic system known as Venona, Ms. Grotjan Feinstein recognized that there were many instances of insecure use of the encrypted communications. This was the critical insight that resulted in the success of the team’s analytical effort. Genevieve Grotjan Feinstein was inducted into the NSA/CSS Cryptologic Hall of Honor in 2010.