She trained to work as a code-breaker with the hope that she would be “doing something that might be useful” in the wake of the Pearl Harbor Attacks that occurred on December 7, 1941(Farley).
Caracristi learned cryptography using William and Elizebeth Friedman’s textbook. She notes that the Friedmans “explained the basis of the way you encrypt material and the way you go about attacking an unknown system.”
Due to the complexity of the codes, training should have taken at least two years for civilian recruits. However, the demand for cryptographers during the War meant Caracristi started her career working at one of the twelve desks allocated to the twenty-six women.
After just six months in the program, Caracristi was already making cryptographical breakthroughs on the “Japanese Problem.” Her focus was on solving additive systems used by the Japanese military and naval forces. Caracristi noted that the problems “did not require a great deal of math, really; they required a great deal of ingenuity” (Sewell).
She approached cryptography with creativity, informed by her studies of humanities, in addition to mathematics and statistics. When asked to describe her time at Arlington Hall, Caracristi stated it was often “me, a cup of coffee, pencil and paper, and stacks of IBM runs, and [my] pencil going across the paper” and that “I found the work exhilarating. … it was like doing crossword puzzles every day and getting most of the answers.”
The department decrypting Japanese messages grew throughout the War until over 66 personnel were decrypting over 55,000 messages monthly between 1942 and 1943. Caracristi was on the cutting edge of cryptanalysis. She recalled being unable to find help because “you assumed that you were going to have to figure your way out of most problems, since they were new problems, newly invented” (Sherman).
She spent much of her time mapping radio transmissions and decrypting Japanese messages. Caracristi and her partner Ben Hazzard worked on solving the Water Transport Code using the 2468 codebook. 2468 refers to the Japanese code which “took a new, third step” to the code-breaking process. Using 2468, the military decrypted thousands of messages.
The largest breakthrough of Caracristi’s career during WWII occurred August 14, 1945, when Caracristi and her team decoded the message which indicated Japanese surrender and an end to the War. After WWII Caracristi spent a year outside the service before she recommitted to Arlington Hall and continued her distinguished career.
For the next thirty-six years, Caracristi worked for the Armed Forces Security Agency, which eventually developed into the National Security Agency (NSA) in 1952. During this time much of her work focused on classified Cold War operations. Caracristi continued to climb through the ranks. In 1959 the NSA promoted her to supergrade, the highest civil service pay grade for women.
President Lyndon B. Johnson recognized Caracristi in 1965, as one of six women selected for the Federal Women's Award; an honor which celebrates “outstanding contributions to the efficiency and quality of the career service of the Federal Government” (Sherman). She used this recognition to advise the President to strengthen equal employment opportunities for women. The President acted on this by passing an executive order in 1967. In 1975 she became the first woman to reach GS-18, which is the highest super grade.
This same year she became Chief of Research and Operations which was responsible for managing the Soviet Union department. Only five years later, in 1980, Caracristi became the first woman to serve as NSA Deputy Director. She served in this capacity for two years until her retirement in 1982. Caracristi’s code-breaking changed the trajectory of the War and left a continuing legacy for the next generation of cryptographers.