Page 326 - The Secret War in the Italian front in WWI (1915-1918)

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

the Sections of the Service. The new S.I.B. - where “B” designates the second version of the SI -
was distributed on 14 October to the abovementioned entities .
26
The S.I.B. included a two-part dictionary with 4-digit code groups and over-encoding tables
marked with numbers from 0 to 9 which convert each pair of digits taken from the dictionary
into two-letter syllables, then grouped in ten-letter pronounceable blocks . In each cryptogram,
27
the tables were changed whenever a sentence ended with ‘STOP’ using the message’s reference
number for choosing the numbers of tables, but backWards. Picture 14.6 shows an excerpt from
the SIB Instruction Handbook that explains how to perform over-encoding.
For messages of a less confidential nature, the Intelligence Service continued to rely on the SI code
while some irrelevant correspondence was still encoded with M13 with over-encoding. There is no
evidence that the S.I.B. code had been adopted by all the correspondents of the Intelligence Service
before the end of the conflict, because of the difficulty to quickly reach some remote locations.
There is evidence, instead, that the S.I.B. - together with the S.I. with grey tables and some other
unbroken systems mentioned above - have remained in force for quite some time even after the
Armistice signature.

14.3 A SHIFT IN THE FORCE RATIO

The unbroken ITalIan cIPhers
The most relevant cryptographic systems likely not broken by the Austrian cryptoanalysts have
been selected and shown in the table below, excluding those used by individual Armies, such as
the Z code, or for specific uses, like FT or C5, despite the lack of any mention from the Austrian
sources. The periods in which some codes remained unsolved, as it occurred to Red and Blu codes,
are also not considered.
Nor any reference is made in the following table on codes eventually derived from the Sacco’s
Small Telephone Code of September 1916, or on the Coding and decoding dictionary entered
service, according to O. Marchetti and Ronge, in June 1917, whose existence could not be proved
with certainty.
The criteria adopted in selecting the cryptographic systems included in the table can be summarised
as follows.
The Green code, very sparingly exploited by the highest Italian Commands and some other Units
after the beginning of the war, does not appear in the Austrian sources, except with reference to
another code with the same colour of the cover but different structure and purpose, being used by
minor units at the local level only.
The temporary structure of D and R codes prevented their general lasting breaks.
As said above, the R, D, together with the I.A. (Inter-Allied), and S.I. (1918 edition) were part of
a short list of unbroken codes and ciphers compiled by O. Marchetti, based on statements made
after the war by imprisoned Austrian officers who served in the Penkala. Moreover, both the S.I.
for the whole of 1918 and the I.A. have never been mentioned by the Austro-Hungarian sources.

26 Intelligence Service, Section R letter, Nuovo Cifrario S.I. (New code SI), October 14, 1918, AUSSME, Series F3, env. 28.
27 Intelligence Service, Istruzioni sulle tabelle pel cifrario SIB, (Instructions concerning tables to be applied to SIB Code),
Library of the ISCAG, Coll. XXXI A, no. 11129.

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