The Forschungsamt was one of the principal German codebreaking agencies of the period 1933-45. Unfortunately we know little about their successes with enemy codes.
Postwar report ‘European Axis signals intelligence vol 1 - Synopsis’, p21-2 admits that no evidence of their cryptanalytic successes were found and that less than 1% of the FA’s personnel were interrogated:
‘No documentary evidence bearing on its cryptanalytic successes was found by TICOM’…………..‘Goering's "Research" Bureau had over 2,000 personnel. Less than one per cent of these were apprehended by TICOM for interrogation’.
In ‘European Axis signals intelligence vol 7 - Goering’s Research Bureau’, p83 it is stated that Polish systems were not solved but only sorted according to link.
However a TICOM report shows that the FA was probably more successful that people think.
From TICOM I-159 ‘Report on GAF Intelligence based on Interrogation of Hauptmann Zetzsche’, p3
9. Intelligence concerning foreign diplomatic exchanges was received from the Forschungsamt (subordinated directly to GOERING) through Ic/Luftwesen/Abwehr, and was given a restricted distribution. It consisted of intercepted Allied radio-telegrams (e.g. London-Stockholm), ordinary radio reports (e.g. Atlantic Radio) and intercepted traffic between diplomats and ministers on certain links, e.g. Ankara-Moscow (Turks), Bern-Washington (Americans), London-Washington (Poles).
10. The last-mentioned source was of great value before and during the invasion and after the breaking-off of Turkish-German relations. In general the Forschungsamt reports contained a great deal of significant information concerning economic and political matters.
Zetzsche was head of Group A of the Luftwaffe’s central evaluation center Foreign Airforces West.
What crypto system was used on this link? What kind of intelligence did the FA people get out of it? What was its value prior and during the Normandy invasion?
If I manage to find more details on this matter I will update this piece.