Etienne Bazeries (1846-1931) was a French military cryptanalyst active between 1890 and the First World War. He is best known for developing the "Bazeries Cylinder", an improved version of the Jefferson cipher cylinder (which was later refined into the US Army M-94 cipher device).
In the 1890s he broke a famous nomenclator system called the Great Cipher, created by Rossignol in the 17th century. His influential 1901 text Les Chiffres secrets dévoilés ("Secret ciphers unveiled") is considered a landmark.
