The Pers Z S was the signals intelligence agency of the German Foreign Office () before and during World War II. It consisted of two cryptologic sections. Pers Z S was the cryptanalytic section which was called Special Service of Z Branch of the Foreign Office Personnel Department (). Its mission was the solution of foreign diplomatic codes and ciphers. The other section, which was the Cryptography Section was called Personal Z Cipher Service of the Federal Foreign Office () (abbr. Pers Z Chi). The latter section was responsible for compilation, distribution and security of Foreign Office codes and ciphers. Both were colloquially known as Pers Z S. Though similar in nature and operation to the OKW/Chi cipher bureau, it was a civilian operation as opposed to the military operation at OKW/Chi and focused primarily on diplomatic communications. According to TICOM interrogators it evinced an extraordinary degree of competence, primarily driven by a consistency of development not found in any other German signals bureau of the period. Pers Z S/Chi was the symbol and the code name of the Chiffrierdienst, i.e. the Cryptanalysis Department of Pers Z S. Although little is known about the organization, in the final analysis, Pers Z S labored at diplomatic cryptanalysis for a regime for which there were no diplomatic solutions.
Short name The abbreviation of "Chi" for the Chiffrierabteilung is, contrary to what one might expect, not the Greek letter Chi, nor anything to do with the chi test, a common cryptographic test used as part of deciphering an enciphered message, and invented by Solomon Kullback, but only to the first three letters of the word Chiffrierabteilung (English: cipher department).
History
Little was known about Pers Z S before April 1945, when the first section was captured. TICOM (Target Intelligence Committee), the United States effort to capture German intelligence assets after the war, found that captured documents provided little information on the execution of the unit, with the records of the Mathematical and Cryptological section having been destroyed. The field covered by Pers Z S, over 25 countries for a period of 25 years, stymied the TICOM as few interrogators were available, and they also lacked experience in cryptographic diplomatic system. This was the first TICOM investigation. Inevitably there were some areas which were not covered.
In May 1945, the usual approach by the TICOM was to force captured personnel to write "homework" describing processes used in a particular intelligence unit under interrogation, but this method was not fully developed. The only document prepared as "homework" was one dated 6 August 1945 by Professor Dr Hans Rohrbach, along with several of his Pers Z S colleagues, which described the cryptanalysis of the American O-2 strip cypher, which was considered a most significant piece of work.I-89
1919–1937
The original name for Pers Z S was unknown but was likely from Political Intelligence Department, and was placed with Bureau I (Abteilung), the normal administrative department in a German government organization at the time. As the cryptography unit grew, it changed its name to Personnel BureauI-1 p. 14 It was later called Chiffrierabteilung, later still the Sonderdienst des Referats Z in der Personalabteilung des Auswärtigen Amtes. In 1925, it was known that both the cryptographic and cryptanalysis were unified under a single director.
In 1919 Kurt Selchow had joined the organization and immediately started to professionalize the cipher bureau. He introduced a system of dividing work upon foreign codes and ciphers into sections for various countries and selected as leaders of these sections men such as Dr Pashke, Dr Kunze, Dr Schauffler who he had known during World War I.I-208
The strength of the organization during this period was unknown. In 1945 Dr Paschke and Dr Schauffler stated that between 20 and 30 people were employed in 1918. A May 1919 list shows 63 personnel employed, and would likely cover clerks, administrators, communications and liaison individuals. By 1930 the Pers Z S unit strength was around 50 personnel.I-22 Statement of Dr Rohrbach, who didn't join Pers Z S until after the war.
1937–1939
On November 1, 1937, Pers Z S had around 77 employees, and by July 1, 1938, this had decreased to 72 people. It was thought that the cryptanalysis unit had around 20 people. Under interrogation, Paschke and Kunze estimated that in 1939, Pers S Z personnel included between 80 and 100 people.I-22 Para 125 A document captured on December 1, 1939, showed a total strength of 92 people,TF 24 but another document stated that 45 new appointments were made between September 1, 1939, and November 1939. Thus it would seem reasonable to assume that at the start of the war Pers Z S had a personnel count of 50.
The available documentation from 1937 to 1939 indicate that Z Branch suffered personnel shortages and a certain inertia within management. The job descriptions (German: Begruendungen) attached to the recommendation for promotion documentation detailed that Dr. Kunze was a Specialist () since 1923 and that Dr Paschke had held the same grade since 1927.
Positions with comparable activities and responsibilities in other ministries are given the grade of Principal Specialist () or Senior Specialist (). This is spite of the fact that the personnel concerned are usually younger and have less time in grade.
Chi complained in 1938 that it could not function efficiently without additional personnel. Ten of its thirteen cryptographers were over fifty years old, six of them over sixty.
Due to the overloading of the cryptographic section, outgoing messages cannot be enciphered and checked with the necessary care. This regrettable state of affair was most noticeable during May 1938 and September 1938, when the political atmosphere was at its tensest.
The cipher bureau was organized as follows:
{| class="wikitable" |- ! colspan=5 style="background:LightSteelBlue"|Group names with director |- ! style="text-align: center;background:#ccc" | Location ! style="text-align: center;background:#ccc" | Unit ! style="text-align: center;background:#ccc" | Strength ! style="text-align: center;background:#ccc" | Total |- | Luisenstift, Managed by Dr Schauffler | Schauffler's Group | style="text-align: center;" | 8
| rowspan="7" | | Paschke's Group | style="text-align: center;" | 13
| Scherschmidt's Group | style="text-align: center;" | 10
| Zastrow's Group | style="text-align: center;" | 9
| Karstien's Group | style="text-align: center;" | 4
| Hagen's Group | style="text-align: center;" | 4
| Records Group | style="text-align: center;" | 3
| Clerical Personnel | style="text-align: center;" | 3 | style="text-align: center;" | 72 |- | Jaegerstrasse 12 III, Managed by Dr Kunze | Special Group Mathematical cryptanalysis | style="text-align: center;" | 20 | style="text-align: center;" | 20
Wartime Little was known about Pers Z at the start of the war.
By October 1, 1940, there were around 290 employees, with Kunze reporting to TICOM that he had 53 people working in his section in January 1941 at the Jaegerstrasse location, and Schauffler reporting that 88 personnel were employed in January 1941, at the Berlin-Dahlem Avenue location. As with other cipher bureaus, similar to the OKW/Chi, the high command bureau and B-Dienst, the Navy cipher bureau, Pers Z S suffered chronic shortage of personnel. On November 26, 1940, Pers Z S submitted a list of problems to high command, primarily due to staff shortages, including 17 major countries which were neglected.TF 24, Letter of Nov. 26, 1940 Doctor Kunze requested an additional 57 employees, 28 of which would be employees on British and American problems and Dr Schauffler requested an additional 17.
Pers Z S underwent no major changes until November–December 1943 when the unit was split into three groups and partially evacuated from Berlin due to continuous bombing by the Allies. Dr Schauffler and Dr Pasche's unit remained in Berlin at Im Dol 2-6,5. The Linguists unit under Dr Karstien, moved to Hischberg in the Giant Mountains. The mathematicians under Dr Kunze, together with all Hollerith machinery were evacuated to Hermsdorf in Silesia. Towards the end of war, in February and March 1945, the unit further fragmented and with the spectre of the Russian advance the personnel located in the Hirschberg group were moved to Burgscheidungen and joined there by some of the former Berlin personnel in April. The organization was knit together by a daily courier service. Later in February 1945 the mathematics based cryptanalysts subsection fragmented with some personnel moving to Mühlhausen, with the majority of the personnel moving to Zscheppelin, a small village, around 15 km west of Delitzsch. No intercept traffic was received after March 1945, however some cryptanalysis continued in Burgscheidungen on archive material, until it was overrun in April.
It is believed that all the Pers Z S archives, which consisted of around 40 chests, went south from Bavaria to Mühlhausen in mid-April 1945. Individual documents in the chests had no markings on them, but the files and folders were marked Geheime Reichssache, Secret Realm.I-172, Section B, Para 19,20
Key personnel
Administrative Section
Minister () Kurt Selchow was Director of the Z Branch. He remained head of the cipher bureau until May 1945.
Senior Specialist (Oberregierungsrat) Dr Roy was head of Administrative Section in Z Branch. He had been with Z Branch since the early 1920s. He was taken prisoner at Mühlhausen in April 1945, but was found to be of little importance to TICOM (the United States Target Intelligence Committee).
Senior Specialist Ernst Hoffman had seniority going back to 1919. From 1940, he was head of the Communication Section in Z Branch, a section newly created at the time.
Senior Specialist Dr Horst Hauthal was head of the Cryptographic Section in Z Branch. His rise in Z Branch was considered meteoric by his peers. He joined the Nazi Party in 1937 and was a committed Nazi. A mathematician, economist, and cryptographer, he joined in January 1940 and was promoted to senior specialist before 1945. After the war he became a German ambassador for the Middle East and North Africa. Later, in the 1960s and early 1970s, he led negotiations for the first bilateral investment treaty with Pakistan.
Linguistics Cryptanalytic Section Senior Specialist (Oberregierungsrat) Dr Rudolf Schauffler, originally a mathematician, was the nominal head of the Linguistics and Cryptanalysis section from at least November 1, 1937, and was the senior cryptanalyst in the section. He joined Z branch immediately after World War I. His main field of interest was theoretical research (German: Grundlagenforschung) on cryptologic methodology.I-22 Paragraph 8 His language specialties were Japanese and Chinese, which was also the cryptanalytic desk he headed. He also served as the primary advisor to the Foreign Office Cryptographic Section (Pers Z S Chi) on Security I-84 Paragraph 11
Senior Specialist Dr Adolf Paschke became joint head of the Linguistics and Cryptanalytics section along with Schauffler during the latter half of World War II. He joined the Foreign Office group in 1919, became a Specialist () in 1927 and became a senior specialist () in 1939. In 1941, he was recommended to the rank of Principal Foreign Office Specialist (Vortragender Legationsrat). He was responsible for report publishing and the translators. He was also responsible for liaison with the German armed forces. His language specialties were Italian, Greek and Russian. Dr Adolf Paschke was a Nazi and joined in 1933.I-172, Section B-1