William F. Friedman -- Master Code-Breaker
June 6, 2014
By Ruth Quinn
In 1933, an American businessman paid $100,000 for the North American rights to a German-made cipher machine invented in 1924. The machine was touted by its inventor as absolutely indecipherable. The businessman submitted an encoded 200-word messaged to the Army's newly created Signals Intelligence Service, or SIS, as a challenge. William Friedman, head of SIS, accepted the challenge, thinking it would be a useful training exercise for his small team of young cryptanalysts. The message was received and date-stamped, "FEB 24 AM 11:12." Friedman scribbled next to the time stamp, "Commenced work. W.F.F." A short time later he annotated, "Time out during lunch period, 50 minutes. W.F.F." Another date-stamp was added at 2:43 p.m. of the same day, over which Friedman wrote: "Solved. W.F.F." The total time elapsed was 3 hours and 31 minutes, less 50 minutes for lunch -- making the solution time 2 hours and 41 minutes. Friedman sent a letter with the deciphered message and the keys back to the lawyer the same afternoon.
This vignette illustrates not only the cryptologic skill of the fledgling SIS team, who broke the code without any machine aids, but also provides a glimpse of the brilliant man behind the organization -- William F. Friedman. A pioneer in the field of cryptology, Friedman became a giant in the industry. Author James R. Chiles called Friedman "the greatest maker and breaker of secret messages in history -- the Harry Houdini of codes and ciphers." Lambros D. Callimahos, a former student, colleague, and friend of Friedman's, compared his mentor to King Midas: "everything he touched turned to plain text." In an article published in 1987, Callimahos summed up Friedman's contribution prior to the war: "Because of Mr. Friedman's foresight and pioneering efforts in cryptanalysis, cryptanalytic training, data processing machine utilization, and cryptanalytic organization, the US Army was fully prepared to meet the Cryptologic challenges of World War II."
William Frederick Friedman was born in 1891 to Russian-Jewish parents who fled to the United States to escape growing anti-Semiticism when William was an infant. When the family's hometown was destroyed and the hundreds of Jews that remained there were killed in 1902, the news of the atrocity haunted Friedman for the rest of his life. However, William grew up in Pennsylvania and graduated from Cornell University in 1914 with a degree in genetics. After graduate school, Friedman was hired to be a geneticist at Riverbank Laboratories in Geneva, Illinois near Chicago.
While at Riverbank, William met and married Elizebeth Smith, an English major who was working in the new field of code-breaking. Not surprisingly, William also became interested in cryptology and by 1917 he and Elizabeth were married and began studying codes exclusively. Together, they spent the better part of a year deciphering messages from unfriendly nations that had been intercepted by the US government but could not be solved. Until the creation of the Army Cipher Bureau in late 1917, Riverbank was the only organization in the country capable of working out these secret messages.
When America entered World War I, the intercepted messages stopped arriving at Riverbank, so Friedman began teaching Army officers the basics of cryptography. He personally conducted three six-week courses in cryptanalysis at Riverbank before receiving a commission and joining those officers in France. During the war, Friedman worked on breaking German codebooks as a member of General John Pershing's staff. Chiles writes, "It was enough time to learn some important things about how armies employed codes and ciphers in wartime, and what could go wrong." Afterwards, he returned to Riverbank, where he completed a publication entitled "The Index of Coincidence and its Applications in Cryptography." David Kahn, author of The Codebreakers, called this booklet "the most important single publication in cryptology. It took the science into a new world."
In 1921, the Army's Chief Signal Officer offered Friedman a trial six-month government contract as a civilian cryptographer. This began William Friedman's 34-year career as an Army employee. By the end of 1921 he was named the Cryptanalyst of the Signal Service, accepting a salary of $4,500 per year. His duties ranged from teaching a course on military codes and ciphers, to writing the Army's first training manual on the topic, called Elements of Cryptanalysis. Friedman published numerous other works throughout the 1920s.
In 1930, Friedman's responsibilities expanded again. With the closing of the Black Chamber, which had evolved from the Army's old Cipher Bureau, the Army quietly transferred the secret code-breaking activities to its new unit under the Signal Corps called the SIS. As Chief of SIS, Friedman had to build a team. His first three recruits were Frank Rowlett, a teacher from a small town in Virginia and Solomon Kullback and Abraham Sinkov, both mathematicians from New York City. (All three would eventually be inducted into the MI Hall of Fame). The small team studied the old files of the Black Chamber, looking for information on Japanese cryptology, read Friedman's booklets, and worked through problems he assigned them. Sinkhov later recalled, "His teaching was such that we developed on our own… He just looked in from time to time to see how we were doing."
When the Japanese replaced their old cipher machine with a much more secure system in 1939, Friedman and his team worked tirelessly to solve the code. Labeled "Purple" by the SIS, the Japanese Foreign Office in Tokyo used the cipher system for its most secret communications with its ambassadors abroad. The team spent 18 months struggling with Purple and trying to figure out the machine that created the code. Then, in 1940, with $684.65 worth of parts, they built a reconstruction of the machine they had never seen, solved the Purple code, and were able to provide plain-text, translated transmissions to the War Department. These intercepts, codenamed "Magic," proved extremely valuable during the war, but the strain of the effort nearly killed Friedman.
Friedman continued his career in cryptology after the war, working for the National Security Agency. He retired from civil service in 1955, but continued to undertake various special and highly secret missions. He died in 1969 and was inducted into the MI Hall of Fame in 1988. William Friedman is a legend in the cryptology world -- his painstaking work, prolific writings, and brilliant accomplishments set a standard in the field that has yet to be challenged.