Signals intelligence and codebreaking operations during the Greek-Italian War of 1940-41

At the start of WWII the Kingdom of Greece, ruled by Ioannis Metaxas  (head of the 4th of August Regime) followed a neutral foreign policy and tried to avoid taking part in the conflict. However constant Italian harassment and provocations (such as the sinking of the cruiser Elli) and the transfer of Italian army units to Albania made it clear that war could not be avoided for long.

In October 1940 Italian forces invaded Greece, in the area of Epirus, and the Greek-Italian war started. The Greek forces were able to contain the assault and the Greek counterattack forced the Italians back into Albanian territory. After the defeat of a major Italian offensive in spring 1941 the front stabilized inside Albania.

At the time Britain was overextended with obligations in Europe, Middle East and Asia. However the British armed forces made a small contribution with an RAF expeditionary corps. When more British forces started to arrive in March 1941, their involvement gave Germany an excuse to become involved in the conflict.

German forces invaded Greece in April 1941 and made rapid progress due to the fact that almost the entire Greek Army was fighting in the Epirus area. The remaining units and the small British forces transferred to Greece in March-April 1941 were unable to stop them. 

Then in May 1941 the Germans were also able to defeat the Greek and British forces that had retreated to the strategic island of Crete.

What role did signals intelligence and codebreaking play during that short conflict? Let’s have a look at the limited information available:

The Italian effort

Italy had two codebreaking departments, one under Army and the other under Navy control.

The Italian army’s intelligence agency SIM (Servizio Informazioni Militari) had a cryptanalytic department that attacked foreign crypto-systems. This section was headed by General Vittorio Gamba and was located in Rome. Personnel strength was roughly 50 people (half cryptanalysts-half linguists and clerks).

The naval intelligence agency SIS (Servizio informazioni Speciali della Royal Marina) was divided into 4 branches. Branch B (Beta) was tasked with signals intelligence. It was subdivided into cryptanalysis, interception and direction finding, security and clandestine radio intercepts. The cryptanalytic department was located in Rome and headed by Commander Mario De Monte.

It is not clear if the Italians had success with Greek Army or Air force codes and ciphers. However in the Archivio dell' Ufficio Storico della Marina Militare there are decoded Greek Navy messages.

Regarding the Greek Air force communications, it seems that the cipher system used was simple transposition (1). Considering the limited security of this system it is reasonable to assume that it was solved by the Italian codebreakers.

The Greek effort

At this time there is almost no information available on the Greek Army’s cryptologic and cryptanalytic effort during WWII. A report from 1938 (2) mentions the Greek Army codebooks: small unit code 1937, large unit code 1937, small unit code 1938, mobilization code 1937, cryptographic lexicon 1935.

Regarding cryptanalysis it seems that the Greek Army Signal Corps may have been able to exploit Italian communications (3). According to an article on Greek military intelligence this information comes from British liaison signal officers:

‘In addition, according to British liaison signals officers, Greek Signals Corps managed to decipher some Italian traffic during the November/December battles in Albania. On 6 December, a British lieutenant-colonel informed his superiors: “Herewith a batch of Italian traffic intercepted by the Greek General Staff. Also, one copy of cipher ‘O.M.’ for internal use of the Italian Army in Albania.” On 8 December, the reply confirmed Greek success: “Many thanks to Greeks for citrario O.M. Tell them I do not remember having seen it but I am very grateful for it and for any further documents of this nature which may be of assistance in reading Italian codes in Albania which I am afraid are not readable.” We could imagine that Greek Signals Corps may have deciphered key traffic during October, prior to the invasion. Unfortunately, at the Army History Service no files of Greek signals operations can be found. Perhaps some material might be held at the Military Archives Service but we must bear in mind that the 1941 German invasion and the 1941-1944 occupation caused the destruction of many files of sensitive army archives. As to Metaxas, he did not make any reference to signals intelligence in his diary’.

The German effort

The German Army’s signal intelligence agency solved Greek Army and Air force ciphers. According to the TICOM report I-170 in spring 1941 Greek AF single transposition messages were solved and translated (4):

My first employment was on the breaking and translating of Greek Air Force messages in Spring 1941. The unit was in BUCHAREST at that time and later it was at BANJA KOSTENIC in Bulgaria. C.O. was Hptm. SCHMIDT, head of the cryptography and translation department from then until Autumn 1944 was Prof. Alfred KNESCHKE, a Professor of Mathematics from Saxony.

The Greek Air Force messages were a matter of simple boxes, the text being sent in T/L groups. The indicator took the form of 3 letters which were always in a given position, the first three T/L groups and had to be knocked out before entering the cipher text in the clear box. This was broken by writing out the cipher text in vertical strips of varying depth and sliding them against each other until a few Greek syllables appeared above one another. After the initial break it became clear that a large part of the messages began with the words ‘parakalw', 'anaferw’ and ‘apesteilamen’ and that the width of the box was as a rule between 15 and 22 columns. On the basis of the above, initial words, all messages were tried out on the normal number of columns and nearly everything was read. I had less to do with the actual evaluation, firstly because the two departments were kept separate and secondly because we were kept fully occupied with our own job. In any case the content of the messages was usually of insignificant strategic value, although the continuous check on officer personalities, deliveries of stores and knowledge of airfields combined with D/F bearings indirectly contributed to considerable tactical results'.

Regarding Greek Army ciphers there is some information available from the postwar interrogations of Army cryptanalyst dr Buggisch. According to TICOM report I-58, in early 1941 he investigated a Greek codebook enciphered with a 35 figure repeating additive sequence (5). Progress was made in the solution of the cipher but the campaign ended just as the system was starting to be exploited operationally:

c. Greek - In early 1941, B. solved a 5-letter code with a 7-cyclic recipherment (period of 35). Just getting to operational speed when the campaign ended.

German exploitation of Italian communications

It seems that the codebreakers of the German Army did not only monitor the communications of their enemies but also solved the codes and ciphers of their Italian allies.

The War Diary of Inspectorate 7/VI shows that Italian codes and ciphers were worked on by Referat 4 (6). According to the reports of Referat 4 for early 1941, 5-figure and 3-figure codes were worked on:

The 3-figure Army code was successfully solved and read. A 5-figure Air Force code was also worked on and the encipherment solved. A 5-figure enciphered code used by the higher command in Albania was worked on and code groups recovered.

The reports say that emphasis was put on the analysis of the systems used by the higher echelons of command.

Some interesting statements regarding Italian radio communications are made in ‘War Secrets in the Ether’ - vol 3, p25 written by Wilhelm Flicke (he was in charge of the OKW/Chi’s Lauf intercept station):

‘Mussolini had decided on war in the Balkans. Von Papen's warnings made Hitler averse to any immediate action there, but he was only able to restrain Mussolini to the extent of limiting Italy to war with Greece. In less than two months the Italians, who had the advantage in everything save morale, were badly beaten. The political leaders were terribly surprised and the Chief of General Staff, Marshal Badoglio, and numerous other high officers were relieved of their duties. This did not help matters.

One of the most decisive factors during those weeks was the manner in which the Italians employed radio. The set-up was the same as that used in maneuvers of previous years. They employed open circular traffic; that is, they used one uniform frequency for a group of stations belonging to the same unit (e.g., the stations of three infantry regiments of a division for traffic with one another and with the divisional station) and each station used only one call sign for all its traffic. The call sign was supposed to change daily but was often used for several days; not infrequently a change in call sign was followed by errors which betrayed the change. Traffic was so heavy that the enemy always had a chance to take bearings and fix locations. Frequently messages were sent in clear. Several units of the Italian Eleventh Army distinguished themselves in this respect. Moreover, the Greeks had obtained at least two Italian army cryptographic systems, how I do not know, but it is certain that in the very first days of the campaign they could decipher a large part of the Italian messages. This enabled them to learn promptly most of the dispositions of the Italian command and to take appropriate action. The superiority thus gained was utilized cleverly and a series of military actions took place which heretofore would never have been deemed possible’.

Notes:

(1). TICOM report I-170 ‘Report on French and Greek Systems by Oberwachtmeister Dr. Otto Karl Winkler of OKH/FNAST 4’

(2). German Foreign Ministry’s Political archive - TICOM collection - file Nr. 3.676 - Griechenland 1940 - Korresp. betr. Neue milit. Schlüssel u. Vernichtung alter.

(3). Journal of Intelligence History: ‘Greek Military Intelligence and the Italian Threat, 1934–1940’

(4). TICOM report I-170 ‘Report on French and Greek Systems by Oberwachtmeister Dr. Otto Karl Winkler of OKH/FNAST 4’,

(5). TICOM report I-58 ‘Interrogation of Dr. Otto Buggisch of OKW/Chi’

(6). Kriegstagebuch Inspectorate 7/VI - German Foreign Ministry’s Political Archive - TICOM collection – files Nr 2.755-2.757

Acknowledgments: I have to thank Enrico Cernuschi for sharing the messages from the Archivio dell' Ufficio Storico della Marina Militare.