"On This Date in Cryptologic History" Calendar
1991: Joseph Mauborgne, code and cipher expert & WWI Army Signal Corps Officer died.
7 June 1991: Joseph Mauborgne, code & cipher expert and WWI Army Signal Corps officer died on this date.
From Wikipedia:
Joseph Mauborgne co-invented the one-time pad with Gilbert Vernam of Bell Labs. In 1914 he published the first recorded solution of the Playfair cipher. Mauborgne became a Major General in the United States Army, and from October 1937 to his retirement in 1941 was the Army's 12th Chief Signal Officer, in command of the Signal Corps.