Update

1). In Soviet codebreakers of WWII i added the following paragraph under Enigma:

On the contrary the recent article ‘О ВКЛАДЕ СОВЕТСКИХ КРИПТОГРАФОВ В ПОБЕДУ ПОД МОСКВОЙ’, says that in late 1942 the Soviet codebreakers analyzed the Enigma cipher machine and developed ways of solving it. However their efforts failed in January 1943 due to German security measures.

This information seems to be confirmed by the war diary of the German Army’s Inspectorate 7/VI. The March 1943 report of Referat 13 (security of German cipher machines) says that based on the published radio dispatches from Stalingrad Inspectorate 7/VI was asked to give an opinion from the point of view of decipherment.

Schlüsselüberwachung

Auf grund der veröffentlichten Funksprüche asus Stalingrad wurde In 7/VI um ein allgemeines Gutachten gebeten, das die Stellungnahme vom Standpunkt der Entzifferung enthält.

Thus it seems that the Soviet effort to decrypt Enigma messages was identified early and countered by the Germans.

2). In Soviet signals intelligence and the German Enigma cipher machine i added:

According to the recent article ‘О ВКЛАДЕ СОВЕТСКИХ КРИПТОГРАФОВ В ПОБЕДУ ПОД МОСКВОЙ’, in late 1942 the Soviet codebreakers analyzed the Enigma cipher machine and developed ways of solving it. However their efforts failed in January 1943 due to new German security measures.

This information seems to be confirmed by the war diary of the German Army’s Inspectorate 7/VI. The March 1943 report of Referat 13 (security of German cipher machines) says that based on the published radio dispatches from Stalingrad Inspectorate 7/VI was asked to give an opinion from the point of view of decipherment.

Schlüsselüberwachung

Auf grund der veröffentlichten Funksprüche asus Stalingrad wurde In 7/VI um ein allgemeines Gutachten gebeten, das die Stellungnahme vom Standpunkt der Entzifferung enthält.

Thus it seems that the Soviet effort to decrypt Enigma messages was identified early and countered by the Germans.