Friedman, William Frederick (1891–1969)

Russian-born US cryptographer, who headed the US government's Signal Intelligence Service (1930) and broke the Japanese ‘Purple’ code (1937–40), thus allowing Americans to read much of Japan's secret messages during World War II. He originally trained as a geneticist, working as head of a lab in Geneva, Illinois (1915–17 and 1919–20). His interest in cryptology led him to set up a cryptology school with his wife for military personnel during World War I. He continued to be involved with American intelligence until 1955, by which time he began to receive wider recognition as one of the world's leading cryptologists. He was born in Kishinev, Russia, and as an infant emigrated to the USA with his parents in 1893.