Page 157 - The Secret War in the Italian front in WWI (1915-1918)

CHAPTER EIGHT

The beginning of the COMINT battle

8.1 THE ITALIAN CRYPTOGRAPHY IN MID-1915

codes wITh dIfferenT levels of secrecy

During the early months of the war, radio communications and related ciphers gradually began to
be used by the Italian army.
The new Red Code, the most common and therefore less secure cipher, entered into force on
midnight between 30 June and 1 July. To increase security, over-encoding was applied to some
correspondence. A number at the beginning of the telegram, immediately after the reference
number, informed the decoding operators that over-encoding had been applied .
1
On the same date, only a few authorities received the new Blue Code, made by only changing
the numbering at the bottom of each page of the Red Code. Despite the ineffectiveness of this
change to protect secrecy, it seems that Austro-Hungarian analysts reached the knowledge about
the existence of the Blue Code only between August and September of 1917. This was probably
due to its lower diffusion than the Red Code and its missing among the codes purchased by the
Austrians before the war .
2
Furthermore, similarly to what had happened in other armies, the Italian army protected confidential
communications between High Commands by means of systems with a higher level of secrecy,
such as the Green Code, directly managed by the Intelligence Office and exclusively designed
for communications between the Supreme Command and the Headquarters of the Armies. Upon
mobilisation, only ten copies of the Green Code had been printed, stemming from a previous 1908
edition that had been revised significantly . The Chief of the Encoding Service of the Supreme
3
Command held one of the copies and few Officers had access to it.
The Green Code - a paged code, too - gradually spread to a limited extent over the following years
for both wire and radio transmissions, yet Austrian sources mention the Green Code only once, but
it does not coincide, in any case, with the code having the same cover colour and used by Italian
High Commands .
4
General Cadorna, Chief of Staff, and his deputy General Carlo Porro were the only holders of
a code with a still higher level of secrecy, and identified with the letters FT. This was used for

1 Intelligence Service, Operations Division, Cipher Section, Service Order 69, Varianti alla corrispondenza in cifra con
l’Addetto Militare a Krakujevato (Serbia) (Changes to the encoded correspondence with the military attaché in Krakujevato),
14 October 1915, AUSSME, Series F1, env.108. A coding group such as 28731 would be transmitted as 13782 and for
increasing secrecy the order of coding groups would be inverted. Simple transpositions such as ROMA - AMOR, were not
a cause of concern for Austrian analysts.
2 O.J. Horak, Oberst a.D. Andreas Figl, op. cit., p.186; M. Ronge, Der Radiohorch, op cit., p.52a. The Blue Code had been
used since the war of Libya and updated for mobilisation.
3 Documentation of the Intelligence Office regarding the distribution of this code in February and March 1915 is in AUSSME,
Series F3, env.52.
4 O.J. Horak, Oberst a.D. Andreas Figl, op. cit., p.165, 305. Figl mentions just once the Green Code, which is not that
mentioned here because he associates it to Divisions communications with Brigades and Regiments. In fact, it coincides with
the Green Code used since January 1918 within the 5 Army Corps.
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