Page 223 - The Secret War in the Italian front in WWI (1915-1918)

CHAPTER TEN

W operating within the 4 Army . As usual, C3 contains two tables: a main table with 17
th
55
columns and 11 or 12 lines, each with a different order of ciphering letters as well as an
auxiliary table with 5 or 6 lines.
However, following the recommendation in Sacco’s report, complete irregularity in
positioning inside the table of letters, syllables, parts of words, words, and numbers from 1
to 100 is finally adopted. Figl recognizes the lack of regularity and repetitions, in addition to
the presence of many homophones: for instance, the word ‘General’ has nine homophones.
Consequently, the difficulty and time required to break the cipher increased considerably
compared to the previous ones. Moreover, the introduction of the mentioned countermeasures
made hard and probably impossible to fully rebuild all the contents of the main table, allowing
only to perform an acceptable interpretation of most dispatches .
56
However, many inaccuracies of the Italian telegraphists in managing the C3 facilitated the
work of Figl and his colleagues. For instance, a service dispatch requesting to repeat the
transmission of a telegram with another code - as the receiving station did not have the C3
- disclosed the very existence and name of the cipher .
57
The Austrians had to make a similar effort to interpret the C4 cipher adopted in April 1917
by radio stations with power equal to or higher than 300 W and consisting of a two-part
dictionary, as shown in the next chapter . The time required to break a cipher is crucial
58
because, when it becomes too long, new ciphers could be adopted at intervals of time so
frequent that they could cause a continuous blackout of the enemy decryption.
Quantifying the amount of time spent by the Austro-Hungarian analysts to break each Italian
cipher is not a simple task, also because their names differ from the Italian ones, producing
some complications in recognising, on each occasion, the equivalence between the two
acronyms . Furthermore, there was often a considerable discrepancy between the dates
59
of the actual adoption of the various ciphers and the dates contained in Figl and Ronge’s
memoirs.
Yet an effort was made to round down the time required to break the single service ciphers from
the date on which they had come into force, achieving the results shown in picture 10.9 which
demonstrates the remarkable increase of that time interval, after the adoption of unordered
systems . Austro-Hungarian analysts were quite concerned about the innovations introduced
60
into the structure of service ciphers as well as about the high frequency of substitutions .
61

55 Chief Inspector of the STM, Military Journal, Lettera con oggetto: Cifrario di Servizio C3 (Letter subject: Service Cipher
C3), 3 November 1916, AUSSME, Series B1, 105 S, Vol.89.
56 O.J. Horak, Oberst a.D. Andreas Figl, op. cit., p.173 -175.
57 ibidem. Obviously, such a repetition is an inexcusable cryptologic error.
58 Chief Inspector of the STM, Military Journal, Ordine di servizio 56 del 26marzo 1917, Cifrario di servizio C4 (Service
Order no. 56 of 26 March 1917, Service Cipher C4), AUSSME, Series B1, 105 S, Vol. 89.
59 As already mentioned in another note, the Austrian name Service Cipher IV corresponds to C2 and the so-called Service
Cipher V corresponds to C4. Oddly enough, the C3 cipher was indicated with the correct acronym and was not classified in
the usual manner.
60 As regards the C3, the date when its structure was finally clear to the Austrian analysts is known (14 January 1917), as
declared by Ronge and Figl. The 1 December 1916 was assumedly the date in which it was first used. The C4 was adopted
st
on 10 April and, according to Ronge, broken in the early days of the Tenth Battle of the Isonzo, which started on 12 May
1917. (M. Ronge, Der Radiohorch, op cit., p.13). The time required for breaking a cipher generally refers to the reconstruction
of the structure of the main tables, not of the sub rows comprising, for instance, the terms frequently used by the Army. In
fact, immediately after the new cipher was introduced, the percentage of identified terms of that kind was low, which did not
prevent more simple dispatches from being understood.
61 M. Ronge, Der Radiohorch, op cit., p.9.

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