Page 178 - The Secret War in the Italian front in WWI (1915-1918)

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

of three-letter Service Ciphers was issued at the same time of the that abolishing partial encoding,
which could have saved this cipher until the following April .
84
Unluckily, despite the official partial encoding withdrawal, the Supreme Command itself allowed
to code only parts of telegrams, sometimes even just a few words .
85
Hybrid encoding implemented by a partial first encoding with Red Code at the Headquarters and
for the remaining words of a message, by Service Ciphers at the telegraphic stations, facilitated the
work of Austro-Hungarian analysts. In fact, this led to a serious cryptographic mistake, because if
the enemy already knew one of the two systems, for example the Red Code, the adopted procedure
practically resulted to be a partial encryption.
However, we cannot agree with Ronge’s assessment that, due to partial coding, “the Italians had
lost the cryptographic war, as had the Russians, ever since the war began” . As a matter of facts, the
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gradual evolution of cryptographic skills - as shown by the events described further on - allowed
the Italians to achieve unquestionable success in this field, above all during the last year of war.
Moreover, despite the overall negative situation, even in 1915 some Italian codes of limited use
and therefore less familiar to the enemy were saved from enemy breaking and, regarding the
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messages encrypted with the Red Code, the Italians enjoyed a ‘temporary’ success starting from
October of that year.
Even before that date, those dispatches were protected by changing the page numbering and/
or by elementary overencoding, not particularly difficult to identify. In October, a measure
consisting of the mere inversion of the numbering of page lines led to a remarkable result
since, according to what Figl himself admitted, it took Austro-Hungarian analysts several
weeks of work to understand this change. This caused a decryption black-out lasting until
12 February 1916, for 112 days .
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8.7 A NEW BRANCH OF INTELLIGENCE: TELEPHONE EAVESDROPPING

The fIrsT deTecTIons
The most common system of telephone eavesdropping during WWI was based upon the combined
effect of electromagnetic induction and interception of electrical current streams in the ground,
generated by the telephone circuits.
If the conversation to be intercepted relies on a ‘mixed circuit’ made of one metallic conductor
with two earth electrodes at the extremities, the return current circulates in the ground, following
variable paths and intensifying in the areas with higher conductivity. A part of such current can
be diverted into a wire terminating with two ground conductors installed in a favourable position,
within the area surrounding the connection to be intercepted. A receiver headset inserted in

84 Chief Inspector of the STM, Military History Journal, Service Order No.20, 6 August 1915, AUSSME, Series B1, 105 S,
Vol. 87.
85 According to a confidential circular letter of the Operations Division of 7 August 1915 signed by L. Cadorna, partial
encoding was still allowed when telegrams did not concern confidential issues but comprised names of persons or army units
to be encoded. This opened a gap in the new regulations.
86 M. Ronge, Der Radiohorch, op. cit., p.3.
87 This happened with the very confidential ciphers for communications between high commands and between higher
commands and the top level of governmental bodies, such as the Green Code, the Blue Code (until its disclosure in 1917)
and with the Service Cipher based on code groups made up of letters, until April 1916.
88 O. J. Horak, Oberst a.D. Andreas Figl, op. cit., p.120 - 123; p. 296.

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