- Author
- Winter, Barbara
- Subjects
- Naval Intelligence, History - WW2
- Tags
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- RAN Ships
- None noted.
- Publication
- March 1991 edition of the Naval Historical Review (all rights reserved)
The book The Ultra Secret by F.W. Winterbotham, has made many people think that the cryptanalysis unit at Bletchley Park was reading German ciphers constantly with the greatest of ease. This impression can be corrected by reading Professor Hinsley or Nigel West, and I do not intend to repeat their excellent work, except to say that the battle against the ciphers was constant, that it was never won completely, and that, of the ciphers used by the German armed forces, the Navy’s were the most difficult to crack, and some were never broken.
The opposite situation existed with respect to British ciphers: at times, the Navy’s seem to have been the easiest to crack, and the German B-Dienst (Beobachtungs-Dienst = Observation Service) had considerable success with them. This analysis is written on the basis only of its reports for November and December 1941. The B-Dienst prepared a weekly B-Bericht (report) based on direction-finding, traffic analysis and cryptanalysis, on reports from agents, and newspaper and radio reports.
By November 1941, 108 individually numbered copies were being produced. They were being issued not only to the naval high command, but also to all pocket battleships and cruises, to destroyer flotilla commanders, to area intelligence officers, and to the High Command of the army and air force. They were leaving Germany to go to area commanders in Norway, France and the Aegean, as well as to attachés or naval missions in Rumania and Italy. Too many people had access to highly secret information which they did not need to know, and this wide distribution endangered security, although the cover carried a warning very similar to the instructions given for handling Enigma/Ultra material: ‘Warning! B-Dienst (wireless interception) requires strictest secrecy! Duplication of any kind and production of extracts are forbidden. B-reports may be passed on only in urgent cases and in an altered form.’
When, in September 1941, the B-Dienst broke back into an important Royal Navy cipher after a long period when it could not be read, the reports were split into two sections, beginning on 3 October, and the production of [X]-B-Reports commenced with No. 39/41. The distribution list was slashed drastically, being 20 circulated and 6 reserve copies on 28 November 1941. Grand Admiral Raeder received Copy 6, Admiral Donitz Copy 4. The commander of the Atlantic air reconnaissance received Copy 5, and other copies went to regional commanders and intelligence officers. Copies were not sent to individual ships or flotilla commanders, and few would have known about these reports. Notably, Hitler was not on the list, and may also not have known that the [X]-B-Reports existed, though he continued to receive the B-Reports. Nor did Admiral Canaris of the Abwehr receive the [X]-B-Reports; indeed, it is not certain that he received the B-Reports; the circulation list contains no mention of the Abwehr, although it contributed information which went into the reports.
The [X]-B-Reports make chilling reading. As circulation was strictly limited, it was possible to put into them more secret information than before, and with the top secret cryptanalysis product omitted from the B-reports, it was possible to increase their circulation without endangering the most vital of secrets. If equivalent Ultra reports exist and were released, it would make the writing of history much easier. Interest centres heavily on the Atlantic convoys and the English Channel, traffic along the east coast of England, the Russian convoys and the situation in the Mediterranean. The few lines with which the East Indies, Asia and Australia were habitually dismissed indicate Germany’s general lack of interest in what was happening in the east.
The preamble to the [X]-B-Reports reads thus: ‘From B-Report No. 39/41, the product of cryptanalysis from the most important English procedures will be made available only to a limited distribution circle, issued in the form of a separate (X)-B-Report as a Command Secret. (Chefsache).
‘It is forbidden to pass on the information in the (X)-B-Report to anyone who is not on the distribution list without urgent operational necessity or to repeat them in the B-Reports.
‘Individual news items in the (X)-B-Reports are always under the same heading as in the B-Reports, so that they can be read in connection with these without difficulty.