A graduate of City College (now City U) New York, Kullback obtained his PhD from GWU in 1934. By this time he had been a member of the United States Army’s Signals Intelligence Service for four years. The war years were busy ones for code-breakers and he was part of the three-man team that broke the Japanese codes. He did not leave the National Security Agency until 1962, when he joined the faculty at GWU where Greenhouse was one of his research students. He received the Wilks Award of the ASA in 1976. Among his other honours was the Legion of Merit from the United States Army.

http://www.nsa.gov/about/cryptologic_heritage/hall_of_honor/1999/kullback.shtml Fuller biography and photograph.