In fact Italian codes were a major target of the German codebreakers from the 1930’s till 1943, when Italy surrendered to the Allies.
The agencies that exploited Italian codes were:
1. The Foreign Ministry’s cryptanalytic department – Pers Z S
3. The Forschungsamt
4. The Army’s OKH/Inspectorate 7/VI
All were quite successful in their work as the Italians were considered to have bad cipher security.
Since compromised Italian codes were a danger to German military units that operated close to them, the Germans tried to get them to upgrade their codes but this did not produce the desired outcome. In one case when a German cryptanalyst told them their codes were insecure he was locked in a room until he could prove it by decoding a message!
The Germans were also interested in the encoded communications of the Vatican. The Pope’s cryptographers however seem to have performed better than their military counterparts, as German successes were limited.
More information is available from the ‘European Axis Signals Intelligence’ volumes and from TICOM reports.
From EASI vol6 – ‘The Foreign Office cryptanalytic section (Pers Z)’ , p29 and p33
Italy. Work on Italian diplomatic codes was an outstanding Pers Z S achievement. From 1935 until late 1942, with lapses as new code books were introduced, Pers Z S apparently read all major Italian diplomatic codes. The 1940 reports from the Italian Group listed twelve codes, enciphered or unenciphered , all of which were read. The work became increasingly difficult in 1942-1943, for the Italians introduced bigram substitution over the additive on the basic code books, ‘’If the basic books had been changed ,the traffic would have been impossible to read”. Some systems 'Were read after the collapse in 1943. Mention was made of Badoglio double transposition system which was never solved. Dr. Paschke mentioned three Neo-Fascist systems which were read in the latter stages or the war.
Vatican The 1940 Report of the Italian Group (Paschke) made it clear that while approximately 50 per cent of the Vatican traffic could be read, the traffic was not a major PerS Z S commitment. Reference was made to a onepart, three-letter code, enciphered by a transposition within the groups, and to a one-part figure code, enciphered by means of substitution alphabets and a sliding strip. Most of the book groups were secured from Goering's "Research" Bureau (FA).
From TICOM I-22 ‘Interrogation of German Cryptographers of Pers Z S Department of the Auswaertiges Amt’, p3
25. Italian: Dr. Paschke was asked what success he had had with Italian systems.He replied that he had been instructed in 1935 to devote special attention to Italian and that the results had been the best imaginable; they had read everything ('Den schonsten Erfolg den man sich denkan kann; es wurde alles gelesen'). In 1942-43 work became increasingly difficult: the Italians increased their subtractor material before the collapse and employed bigram substitution over a subtractor over a book. If they had changed the book, the traffic would have become 'impossible' to read. After the collapse they read a Government code ‘Impero’ recyphered with figures from the encode, with little depth. Later the Government systems were not read for lack of depth, but it was thought that they used double transposition. The Neofascists had used a 5,000 figure subtractor; the peculiar systematic arrangement of the figures in the subtractor assisted solution very much. In the last three months the Neofascists had used unrecyphered books which were easily read, and an alphabetical book with a short subtractor called RA 1.
From EASI vol3 - ‘Signal Intelligence Agency of the Supreme Command Armed Forces’ (OKW/Chi) , p67 and p69
Senior Specialist Raffel was head of the Italian desk. The section contained thirty-five to forty people and apparently had considerable success. Senior Specialist Paschke, of the Foreign Office Cryptanalytic Section (Pers Z S), said that between 1935 and 1942 his people had "read everything' in Italian, and it is likely that their results were passed on to OKW/Chi. We know that OKW/Chi read a diplomatic system called AR 22, and the Impero Code. Between 1942 and 1943 the Italians increased their additive material and employed digraphic substitution. After the surrender of the Italian Government, the Impero Code continued to be read by the Foreign Office Cryptanalytic Section (Pers Z S) for a while. Later, there was no longer sufficient depth to do this and it was suspected that a double transposition was being employed. The systems of the Neofascist Italian Republic were also read by the Foreign Office Cryptanalytic Section (Pers Z S). They used a 5,000-figure additive; during the last three months, they also used unenciphered books and an alphabetical book with a short additive called RA 1.
Around the beginning of the war, a desk was established for attacks on Vatican traffic. Seifert, a former member of the Austrian Cryptanalytic Bureau, joined OKW/Chi at the time of the Anschluss and broke a Vatican book.
From TICOM I-21 ‘Preliminary Interrogation of Oberst Kettler, R.R. Dr.Huettenhain Sdf Dr. Fricke and ObIt. Schubert (OKW/Chi), 15 June 1945’, p3
Q: What work did you do on Italian ciphers ?
Huettenhain : We worked on them with success. We told the Italians but at first they refused to believe it.To prove it to them we finally sent a cryptographer to Rome and he was locked in a room until he had done so!
From EASI vol7 – ‘Goering’s Research Bureau (Forschungsamt) , p82 and p88
Italian Systems.Enciphered code ,
Rentschler claimed some success on high grade Italian diplomatic systems. The Annual Report of the Italian Group of Pers Z S for 1940 indicated a fairly extensive Pers Z S - FA cooperation on Italian systems. Intercept of the FA was made available to the Foreign Office and from 1939 through 1940 there was a regular exchange of encipherment tables. In September 1940 and in November 1940 there was a mutual exchange of book groups on two codes AR 38 and RA 1.
Vatican Systems.Vatican Code.
In a captured Pers Z S reconstruction of a Vatican Code Book the signature of a Fraulien Titschak appears with the date of August 1939 and a notation that she had copied out values at that time for the FA (Fraulien Titschak was a member the the Foreign Office Cryptanalytic Bureau) .The Annual report of the Italian Group, of Pers Z S for 1940 indicates that while Pers Z S did some work on Vatican systems most or the identifications on Vatican systems were received , from the FA.
From TICOM I-78 ‘Interrogation of Oberstlt. Mettig on the History and Achievements of OKH/AHA/ln 7/VI’, p11
This section specialised in watching Italian traffic which was very insecure and most of which was read by the Germans, especially traffic from ITALY to NORTH AFRICA. In 1941 Hptm Dr FIALLA paid a visit to ROME, notified the Italians of their Weakness and requested greater security. In spring 1942 Hptm BIGGI of the Italian Army paid a return visit to In 7/VI and was enlightened as to the German use of Hollerith machines. The renewed request to the Italian for greater security in their cipher methods failed, just as the Italians were unable to set up their own Hollerith section. In 7/VI had not, in any case, the authority to put any pressure on the Italians, moreover, the general opinion was that the Italian cipher department under Gen GAMBA was not competent enough to institute changes; (in matters of agents' ciphers the Italian section was more efficient). It was assumed by In 7/VI that German troop movements in AFRICA were betrayed to the British by the insecure Italian wireless.
From TICOM I-100 ‘Report by Uffz. Herzfeld of NAAST 5 (Gen. d. NA) on the Work of the Italian Referat of In 7/VI’, p2 :
In the beginning of September 1943 an Italian reciphering table and a number of messages from the cipher office of the Italian Commandantura at ATHENS arrived in BERLIN. They had been taken by some German officers under dramatic circumstances. When the news that MUSSOLINI had been arrested and that the Italian government had concluded on armistice, was received at German Headquarters in ATHENS, two lieutenants of Kommandeur der Nachrichtenauflaarung at NEA PHALIRON drove to the commandantura in ODOS AMERIKIS in ATHENS, walked into the cipher office and started collecting the material lying on the tables in the office and packing it into a case in front of the bewildered cipher personnel. They were in the middle of doing so when a number of Italian officers came in and began shouting rather excitedly. After some controversy the Germans thought it preferable to disappear quietly since the attitude of the Italians became too threatening. They did however carry with them what they had collected from the tables and sent it on to BERLIN where PW was charged with trying to find out what it was worth.
PW resumed his work there, but in November 1943 Major LECHNER decided to dissolve the Italian Referat, a decision justified by the fact that after the fall of LEROS no more Italian wireless messages could be intercepted. It was believed that the Allies had prohibited further Italian Wireless transmissions.
In the end Italian cipher security remained low (although some of their high level codes proved too much even for Bletchley Park!) and certainly had unfortunate consequences for them and their German allies. Perhaps the Germans could have changed that by being completely honest with the Italians and presenting them with the full record of their success against their codes. Then again that would mean that they would lose their ability to closely monitor their ally’s moves. Choices, choices….