Frank B. Rowlett

Frank B. Rowlett was an American cryptanalyst recruited by William F. Friedman to the U.S. Army Signal Intelligence Service in 1930. He became a central figure in the small group that developed U.S. cryptologic capability before and during the Second World War.

Cryptanalysis and protection

Rowlett participated in work against Japanese diplomatic systems known to U.S. analysts as RED and PURPLE. He also helped with the design of SIGABA, a U.S. cipher machine whose wartime security against Axis cryptanalysis was a notable communications-security achievement.

Later service

After senior roles in precursor agencies and the CIA, Rowlett returned to NSA and became commandant of the National Cryptologic School. This sequence connects analysis, secure design, and professional education.

In memoriam

Rowlett died in 1998. The NSA's Rowlett Awards continue to recognize information-assurance work in his name.

Timeline

• 1908-05-02Born in Rose Hill, Virginia.
• 1930Joins the Army Signal Intelligence Service as a junior cryptanalyst.
• 1930sWorks on Japanese diplomatic systems including RED.
• 1939-1940Plays a major role in solving the Japanese diplomatic system called PURPLE.
• 1965Becomes commandant of the National Cryptologic School.
• 1998-06-29Dies at age 90.