Otto Buggisch (28 June 1910 – 15 September 1991) was a German mathematician who, during World War II, was a cryptanalyst working in the cipher bureau, the Cipher Department of the High Command of the Wehrmacht (OKW/Chi) responsible for deciphering of the opposing forces Communications. He also dealt with the security control of own key procedures. Through research and revelations exposed by two Polish officers, late in the war, he recognized the true cryptographic weaknesses of the Enigma rotor cipher, key machine used by the German armed forces to encrypt their secret communications, in World War II.
Life
Buggisch graduated from the Ludwig-Georgs Gymnasium (LGG) in Darmstadt in 1928. He studied pure mathematics and physics and the subsidiary subject applied mathematics at the Technische Universität Darmstadt. In 1938, Buggisch was promoted to Dr. rer. nat. with a mathematical dissertation titled On the Rarity of Equations with Affect (German: Über die Seltenheit der Gleichungen mit Affekt) which was supervised by Udo Wegner at the Technische Universität Darmstadt. During the war, Buggisch held the military rank of a sergeant in group 7/VI at OKW/Chi.
Military career
1940 From May 1940 to July 40, Buggisch was posted to a Wireless Telegraphy (abbr. W/T) Listening Interpretation Station (colloquially Out-Station or Intercept station) of Army Group C in Bad Schwalbach, Bad Kreuznach, Saarbrücken. Buggisch was subordinated to Hauptmann Walter Mettig, a signals officer, who became second-in-command of OKW/Chi. Together with his colleague, the mathematician, Wolfgang Franz, they initially worked on French Army cipher systems before and during the Battle of France. These were the F90, F110 ciphers, known by their German designations and were based on 4-figure codes. In one case the recipher consisted of a periodic adder, or subtractor of length 11. In the other, it was ordinary transposition, the transposition key being obtained from a key word which itself was taken from the code and shown by an indicator group. Both systems were being read from the winter of 1939 to the end of the Battle of France in June 1940. Buggisch also worked on analysing the diagonal write-out transposition (Transposition cipher), C-36 cipher machine These were simple field codes. From 20 July 1940, he was posted and attached to an intercept station in Berlin at 29/30 Bendlerstrasse, where there were other specialist sections for interception of Russian and Balkan traffic. During this period, he undertook the completion of two works on the C-36 Cipher machine, while working with the team which included Erich Hüttenhain, the chief cryptanalyst of OKW/Chi and Fritz Menzer, the hand and machine cipher designer and inventor. Buggisch also studied the M40 device, designed by Fritz Menzer, finding it moderately secure but it was never actually used. The M40 device was the forerunner of the Cipher Machine 41 (German: Schlüsselgerät 41), but the motion of the wheels was found to be not so irregular. During September 1940, Buggisch was transferred to a Soviet (Russian) specialist section. They worked on a 4-figure code (Olowo) and 5-figure codes, creating practice messages. In October or November 1940, Buggisch transferred to an intercept station in France.
1941 In January 1941, he was transferred to the Balkans specialist section that was directed by Rudolf Bailovic. Buggisch worked on the Greek 5-figure transposition cipher. Two memoranda were issued concerning the JUGO – SLAV code. Around 1 February 1941, all cryptanlysts including Buggisch were transferred from the Intercept station to the Inspectorate 7 unit, later called the General der Nachrichtenaufklärung. In June 1941, Buggisch moved to the newly formed Signals Recce Abteilung (abbr. Signals), with all personnel who worked in In 7/VI being subordinated into that unit. The Russian cipher specialist section was again subordinated to the Intercept station, with the unit moving to Loetzen. Between July 1941 and November 1941, while at Loetzen, Buggisch worked on 5-figure material, specifically the OK40 code and the K37 machine. The OK40 was the official Russian designation for the Soviet (Russian) 5/F or 5-figure operational code. It contained 25,000 groups namely all the five-figure numbers and only these, in which the first three figures were all simultaneously odd or simultaneously even. For recyphering the add [subtractor] or 300 5/F groups were in general use by the Soviets. The code was used from about the end of June 1941 to September 1941, by the higher and highest Soviet Army command. Soon after the beginning of Operation Barbarossa, several copies of the code were captured along with their recypher tables but with most of them out of date by that point, with the Soviets changing them frequently, but not yet daily. Owing to the already mentioned special characteristic of the first three elements of the code groups it was particularly easy to line them up. In this way, depth of 8–12 was often obtained, so that the recipher could easily be stripped by well known methods. The K37 was the Russian Crystal cipher machine, that worked on the same principle as the B211 cipher, but a more primitive cipher. The K37 machine was different from the B211 in lacking the (German: Surchiffreur) or German: Ueberschluesseler, a sort of Enigma wheel by which the path of the current was turned to another channel at one point, crossing over and exchanging positions with another path instead of continuing parallel. Buggisch called this the X effect, and stated it greatly complicated cryptanalysis, as it was hard to tell when it was being employed in place of the parallels. A model was captured in 1941. Analysis by Buggisch and Herbert von Denffer found that it could be solved on a 10 letter crib. The work remained purely theoretical as no traffic from this machine was ever received. In November 1941, Buggisch was transferred to In 7/VI in Berlin, working at the French specialist section, located at Matthekirchplatz 4. Posted there until August 1942, he worked on a variety of problems, including
Hatted diplomatic 5-figure codes used by Charles de Gaulle Swiss Hagelin machine messages. The unit included Dr Kunze of Pers Z S, working on French diagonal write-out transposition ciphers used by the de Gaulle delegation in Senegal.
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