World War I cryptography

The use of these codes required the distribution of codebooks to military personnel, which proved to be a security liability since these books could be stolen by enemy forces.

At the beginning of the war, France had eight intercept stations: Maubeuge, Verdun, Toul, Epinal, Belfort, Lille, Rheims, and Besançon.

[5] The ADFGX and ADFGVX field ciphers were a modified polybius system with single order double columnar transposition and frequent key change, with letters optimized for Morse.

The breaking of the ADFGX cipher by Painvin was the second time during the war that cryptanalysis played a major role in shaping events (the first being the interception and cracking of the Zimmerman Telegram).

He later headed the Cipher Bureau, a new cryptanalysis group started in 1919, immediately after World War I, and funded jointly by the State Department and the US Army.

Some American cryptography in World War I was done at the Riverbank Laboratories, Chicago, which was privately owned by Colonel George Fabyan.