Page 151 - The Secret War in the Italian front in WWI (1915-1918)

CHAPTER SEVEN

7.11 Cover and first instructions page of the Pocket Military Cipher

The PockeT MIlITary cIPher
In 1901, when the Headquarters of General Staff decided to also provide subordinate units of the Italian
army with a cipher, Felice De Chaurand de Saint Eustache presumably created the Pocket Military Cipher.
The 1915 edition directly stemmed from the 1901 (picture 7.11) edition with some minor changes in the
instruction manual. The Instructions of 1915 edition openly state that “the two mobilization coding systems
of the Army - the Pocket Military Cipher and the Red Cover dictionary - were in use since peacetime by
various Arms, Corps and Services” , further specifying that “Commands at the lower level than Division
46
were equipped with the Pocket Military Cipher only, while higher-level commands had both” .
47
The Pocket Military Cipher required for its practical appliance just one table (picture 7.12)
contained in single page which could be folded and held in one’s pocket. In addition, it was easy to
reconstruct, as necessary for communications of units operating in forwards areas of the front line.
This cipher adopts a poly-alphabetic literal substitution method where each plaintext letter or
number is replaced by a letter or symbol of another alphabet that varies according to a set key, as
in the ‘square table’ improperly called Vigenére table. The Pocket Military Cipher differs from
the original Vigenére because, instead of the letter of the alphabet comprised in the square table,

46 Ministry of War, Headquarters of the General Staff Corps, Istruzione sul Cifrario Militare Tascabile (Instructions for the
Pocket Military Cipher) Rome, January 1901 (reprint June 1915), p 11, 12, AUSSME, Series H 5, env.11.
47 Lower-level Headquarters are: Brigade HQ of the Royal Carabineri, of Infantry and of Cavalry; Regiment HQ of the Royal
Carabinieri, of Infantry, of the Bersaglieri and of the Alpini battalion; HQ of the Artillery, of the Engineer Corps, of the
Medical Commissariat of Army Corps; Bycicle Company HQ; Regional HQ and Costline Company HQ; Fort HQ.

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