Page 128 - The Secret War in the Italian front in WWI (1915-1918)

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

encoding and the corresponding decoding process of dispatches can take place near their origin
- generally speaking, at the code offices of emitting Headquarters - or at the premises in charge
of transmitting and receiving the dispatches, namely telegraphic or radiotelegraphic stations or
telephone operators. In fact, very often during the war, radio stations not only encoded and decoded
service messages, but performed the same task also for telegrams originated by and sent to various
units and Headquarters. For both those purposes, they employed the so called Service Ciphers.
The transmission medium indicated in the picture may be physical (overhead wire or cable) or
radio, with consequent changes of the transmitter and receiver structure.
Interception operations do not generally interfere with the transmitted signal, facilitating the
detection immunity, although, in some cases, certain signals could indicate enemy activities that
may have already occurred, be underway or possible. For instance, listening to enemy conversations
during a telephone communication is a clear sign that the talkers can be intercepted in turn.
The picture also shows a single distribution channel for both ciphers and keys. The relevance of
those channels and the reasons for eventually choosing different communication ways for ciphers
and keys will discussed further ahead.

requIred characTerIsTIcs of codes and cIPhers
The two fundamental requirements in designing a cipher or a code are their security and quickness.
For some applications, security achieved by a robust encryption, result to be a must, while in
others, the need to ensure quickness and simplicity of encoding and decoding becomes prevalent,
without neglecting the warranty of the secrecy along a time interval consistent with the dispatches
contents.
Therefore, at the beginning of the war, most of the armies was equipped with at least two different
types of ciphers and codes alternatively used according to the degree of security and to the encoding
and decoding operation conditions. One category aimed to protect communications of a strategic
nature between high commands, while the other was suitable for tactical communications with
and between subordinate units. In the first case, complex codes and relatively bulky manuals were
exploited, with the purpose of increasing difficulty and time needed for dispatches’ interpretation,
while forgoing quickness operations to a reasonable extent. On the other hand, lower-level units
were equipped with simple and handy ciphers which involve a limited time for encoding and
decoding operations and may be quickly replaceable when lost, but structured for delaying
interpretation of cryptograms by the enemy the time necessary to render obsolete the information
contained therein.
In addition to being secure, quick, and simple in decrypting dispatches, military codes and ciphers
also need to be extremely reliable in terms of precision and accuracy. Those characteristics are
essential to minimize, the probability of error in the encoding and decoding operations, thus
avoiding repetition of messages or, even worse, their misinterpretation.
It is also obvious that coding operations should not imply an increase in length of the cryptogram
compared to the plaintext.
During the war, the number of codes with specific purposes (air force communication, weather
forecasts, etc.) multiplied for all armies and moreover many units developed systems for their
internal use. Therefore, in order to grant suitable levels of security, meeting the above-mentioned
criteria and others specifically related to each application, centres with high-level cryptologic
capabilities were set up in many armies, in charge of controlling the characteristics of codes and
ciphers produced by people often without the necessary cryptologic knowledge.

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