Wolfe Frederick Friedman, the son of an interpreter, was born Kishinev, Russia, on 24th September 1891. The following year the family emigrated to United States to escape increasing persecution of Jews in Russia. The family settled in Pittsburgh in 1893. As a child his forename was changed from Wolfe to William.
After graduating from Cornell University, Friedman began work for Riverbank Laboratories in Chicago. There he became interested in the study of codes and ciphers and during the First World War became a cryptologic officer with the U.S. War Department in Washington.
In 1921 he was appointed as the War Department's chief cryptanalyst. On the outbreak of the Second World War Friedman became involved in Magic, the codename given for the American operation to break the Japanese diplomatic and military codes. The Communication Special Unit (US Navy) and the Signals Intelligence Section (US Army) worked together in monitoring the traffic of coded messages sent by the Japanese Government and the Imperial Headquarters to their commanders at sea and in the field.
In 1939 Japan began using a new cipher machine invented by Jinsaburo Ito. Nicknamed the Purple Machine, the code was not broken until September 1940 by Friedman and his team. However, because of the large volume of intelligence being received by the staff of Magic, they were unable to give adequate warnings about the proposed attack at Pearl Harbor.
With increases in the number of people working at Magic they were able to discover the attack plan at the Battle of Midway. This enabled Admiral Chester Nimitz to use this information to fight off a much larger force and halt the Japanese offensive in the Pacific.
In January 1944 Colonel Friedman collapsed from overwork and was in Walter Reed Hospital for three months and was eventually given a honorable discharge.
Friedman became director of Communications Research in the Army Security Agency. William Friedman retired in 1955 and died of a heart attack on 2nd November, 1969.