The Black Code (more formally, Military Intelligence Code No. 11)[1] was a secret code used by US military attachés in the early period of World War II. The nickname derived from the color of the superencipherment tables/codebook binding.[2] The code was compromised by Axis intelligence, the information leak costing a great many British lives.
- ^ "European Axis Signal Intelligence in World War II, Volume I, Synopsis. DOC ID 3560861" (PDF). Army Security Agency. Retrieved 2017-09-10.
- ^ David Kahn The Codebreakers – The Story of Secret Writing (ISBN 0-684-83130-9)