Page 222 - The Secret War in the Italian front in WWI (1915-1918)

THE SECRET WAR ON THE ITALIAN FRONT IN WWI (1915 – 1918)

an InnovaTIve conTrIbuTIon
The Small Telephone Code is a two-part dictionary with an encoding part and a decoding part. The
plaintext terms include syllables, alphabet letters, numbers from 0 to 9 and many terms currently
used within the Italian army, as shown in Annex C where copies of the introduction and of the
two opening pages for the coding and decoding parts are shown. Each plaintext term listed in
alphabetical order in the first part corresponds to a three-figure number to be drawn, in each groups
of Army units having in common the same version of the code. In the decoding part, the numbers
listed in an increasing order were not associated to the corresponding plaintext, before the draw.
It should be noted the abundance of homophones, together the possibility of introducing in the
cryptograms many null code groups because the items within the range between 000 and 999,
amount to just 550. To avoid errors in transmitting figures, Sacco added a dictionary converting
code groups into geographical names, as partially displayed in Annex C.
In compliance with the general principles of Sacco’s report, the “ensemble of the randomly drawn
numbers of the coding part” may be assumed as the code key “which must be different in any sector
of the front and change at least every month” . Therefore, every operational unit had to draw the
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code groups valid inside its own organization, at least ones a month.
It is easy to understand that the proliferation of temporary codes thus obtained, along with the
expedient consisting of dividing, when necessary, words, signatures, etc. into syllables and letters
in ever-different ways can make enemy analysts’ life quite difficult. How appropriate it would have
been to immediately apply Sacco’s principles to all Italian radio communications!
The Small Telephone Code does not only represent a mere example for demonstration purposes,
but a precursory pattern for the cryptographic method that would be applied, with considerable
difficulty and delays, over the following years. In fact, the criteria adopted provided the basis for
some codes introduced during 1917 and 1918 that Austrian analysts could never break. It cannot
also be excluded that the code in question, or other versions of it, were employed by some units
of the Army.
Sacco’s proposal should be considered as innovative mainly in terms of the drawing methodology
that, starting from a single book, could easily generate, many codes independently renewable.
Other armies, including the German and the Austrian ones adopted in their cryptographic systems
some forms of drawing, during the last months of the war.
Basically, this kind of codes fully complies with the Kerckhoffs principle, according to which the
enemies might know the systems, but they would not necessarily be able to decrypt dispatches
without the key which, as Sacco correctly points out, consisted in this case, of the random sequence
of code groups.
It is worth noticing that this method also represents a solution for the issue of the distribution
of ciphers and, above all, of keys becoming increasingly complex due to the large spread of
telecommunications, and especially of the radio, in the most forward areas of the front.

The new servIce cIPhers
Between late November and early December 1916, Austrian analysts had an increasingly
hard time breaking the new ciphers of the Italian radio services. This happened for the first
time with the C3 cipher, initially applied by stations with power equal or lower than 200

54 ibidem

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