Signal Intelligence Service

Friedman was a geneticist who developed his expertise in cryptology at George Fabyan's Riverbank Laboratories Cipher Department during 1915 to 1917, prior to World War I.

The SIS initially worked on an extremely limited budget, lacking the equipment it needed so that the analysts could intercept messages to practice decrypting.

Ann Z. Caracristi, who would later become Deputy Director of the National Security Agency, started her career there and was a prolific breaker of Japanese army codes.

The unit she worked in, largely staffed and led by women, produced a flow of intercepts from the "2468" shipping code system that resulted in the sinking of two-thirds of the Japanese merchant marine.

Decrypted messages revealed the existence of Soviet espionage at the Los Alamos National Laboratory work on the top-secret Manhattan Project, where the atomic bomb had been developed and research continued.

The Venona project was so highly classified, however, that the government never introduced evidence from these messages into court proceedings in prosecution of alleged espionage agents.