Page 221 - The Secret War in the Italian front in WWI (1915-1918)

CHAPTER TEN

10.4 ABOUT THE SAFETY OF ITALIAN RADIO COMMUNICATIONS

a cryPTograPhIc rePorT by luIgI sacco

In 1916, the Cryptographic Units, focussed more on breaking ciphers and decrypting enemy
dispatches rather than on designing codes and ciphers that could be safer than those used, until
then, by the Italian army. On the other hand, the implementation of ciphers and codes that would
take weeks or even months rather than a few hours or days to be solved, would require not only
adequate amount of trained human resources, but also the assignment of a formal task, needful to
intervene effectively in a very ‘sensitive’ area, especially for the aversion shown by cipher offices
of High Commands to change or introduce alleged complications in their work.
Notwithstanding the absence of an official mandate, Captain Sacco - keenly aware of the binding
need to improve the critical situation of Italian cryptography - wrote in early September 1916 a
report in which, while highlighting the weakness of the codes and ciphers used by the Army, he
identified the paths to create safer systems .
52
The report where Sacco recommends “deliberately avoiding, in our coding systems, anything that
could help the enemy decrypt our dispatches”, is enclosed integrally in Annex C. In five-page
extremely clear and simple overview, he describes the methods to decrypt the Pocket Military
Cipher and dictionaries such as Red Code and Mengarini Code, proving their considerable
weakness.
The author then lists some general rules to prevent decryption by the Austrians, and suggests
avoiding:
– any symmetry and uniformity in ciphers;
– the accumulation, in the enemy’s hands, of copious cryptographic material coded with the same
system and the same key;
– the frequent repetition of the same code groups in a cryptogram or in subsequent cryptograms;
– the inclusion of plaintext words into encoded texts even when these had low level confidentiality.
To overcome the mentioned weakness, he recommends to frequently change the coding systems
and keys, to introduce homophones for the most common terms and to employ the double coding
which allows to modify “the code groups occurrence, compared to the natural occurrences of the
Italian language”.
Given the clarity and accuracy of this analysis, it arouses wonder about the slowness of application
in Italian army of the criteria suggested by Sacco and about the long and arduous process required
for the adoption of innovative codes and ciphers.
In fact, Sacco did not only expose a diagnosis the of Italian military cryptography evils and suggest
ways to remedy them, but as evidence of the set out principles, wrote a Piccolo cifrario telefonico
(Small Telephone Code) that “when used rationally and with frequently changing keys, provides
little help to the analysts” . In contradiction with its reductive name, probably adopted for avoiding
53
frictions with various Headquarters, this vocabulary can be considered as one advanced example
of trench code (carnet de chiffre): a code family originally created for telephone communications
and then used, also for radio telegraphy by many fighting armies between the end of 1917 and the
beginning of 1918.

52 L. Sacco, Notizie sui sistemi di decifrazione e norme per il ciframento dei telegrammi, (Information about decrypting
systems and rules for coding telegrams) Codroipo, 2 September 1916, ISCAG, Coll. 223.
53 ibidem.

219