Étienne BazeriesEtienne Bazeries
) 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.