"On This Date in History" Calendar
1935: Navy cryptologic organization redesignated OP-20-G as Communications Security Group.
11 March 1935: Between 1924 and 1935, the Naval cryptology service developed operationally, culminating in the formation of the Communications Security Group (CSG), effective 11 March 1935. That date marks the first appearance of the word "Group" in the title of the Naval cryptology organization and is observed as the birth of the Naval Security Group.
