Captain Dyer - Cryptologist Number ONE ?

Captain Thomas Dyer, as Admiral Nimitz's intelligence officer, was directly involved with the interception, decryption, and subsequent intelligence information reporting which led to the shootdown and death of Fleet Admiral Isoroku Yamamoto. His efforts led to the breaking of the Japanese merchant shipping and transport code and the main Japanese weather code.

From February 1946 to June 1949, Dyer was assigned to the Naval Security Station, 3801 Nebraska Avenue, Communications Support Activity in Washington, DC (precursor to the Naval Security Group) as chief of processing and technical director. In 1947, he was designated the first (?) Navy Special Duty Officer (Cryptology). Dyer was a leading member of the Navy contingent that joined the fledgling Armed Forces Security Agency in June 1949 and, along with Captain Laurance Safford, was in charge of all daily AFSA operations.

Taken from the National Security Agency website.