GERMANY'S FIRST CRYPTANALYSIS ON THE WESTERN FRONT: DECRYPTING BRITISH AND FRENCH NAVAL CIPHERS IN WORLD WAR I

But as the Allied naval activities against the German submarines increased, so did the volume of decryptable material. Surveillance Command handled 5883 telegrams in August, 6897 in September, 7201 in October, and 9208 in November, and the growing complexity of the British naval ciphers meant that the workload grew considerably. Nevertheless, the tactically important reports forwarded to the navy by teleprinter increased continually, from 1751 in August, 1954 in September, 2051 in October and 2193 in November. And due to the lack of qualified staff, Surveillance Command was forced to concentrate its efforts on the three main enemy ciphers.39

When Surveillance Command asked for additional staff in view of this development, the military authorities decided to double decryption capability by instead setting up a second Surveillance Command. This demonstrates to what extent Germany still believed that additional naval decrypts would further enhance the effectiveness of the unlimited U-boat war. In January 1918, Bavarian W/T Surveillance Command No. 2 was established. It was attached to the former Bavarian XV Reserve Corps, which in the summer of 1915 had been upgraded to Army of the South (Sudarmee) and was stationed in the southern part of the Eastern Front. Its surviving files suggest that it covered the Eastern Mediterranean and the Black Sea.40

By then Foppl had left Surveillance Command.

In autumn 1917, the German military authorities united all units handling signals into a single organisation which was named Signals Service (Nachrichtenwesen). Commanders of Signals (Nachrichtenkommandeure) were established down to division level. As part of the reorganisation, decryption and interpretation of the enemy army signals were fused at division, corps, and army level. The new offices, set up in November 1917, were named Evaluation Offices (Auswertungsstellen) and attached to the staff of the respective Commander of Signals. These offices interpreted all observations resulting from the interception of enemy communications and decrypted all intercepted information as completely as possible. But they were expressly forbidden to try to find the keys of enemy ciphers. This was the prerogative of the Evaluation Offices at army level.41

The Sixth Army appointed Ludwig Föppl head of its newly created Evaluation Office. Prom then on, he was in charge of decrypting British and French army communication for the Sixth Army. The cryptanalysts of the Sixth Army were by now considered to be the leading experts in their field and were consulted whenever difficulties appeared that others felt unable to handle themselves. The Evaluation Office of the Commander of Signals Service (Chef des Nachrichtenwesens) at the Supreme Army Command and other offices sent voluminous material for solution. Both the Sixth Army Evaluation Office and the Surveillance Command No. 1 were part of the staff of the commander of Army Signals of the Sixth Army, and both sent their reports to the Evaluation Office of the Commander of Signals Service at the Supreme Army Command.42