|The Flossenbürg Messages|
Photo: KZ-Gedenkstätte-Flossenbürg © 2005
During an ongoing project of decoding 60 year old German Army Enigma ciphers we have come across a large number of enciphered radio messages from and to the concentration camp Flossenbürg. The messages, 258 in total, are enciphered on the Wehrmacht Enigma machine using a special concentration camp key, KL-Maschinenschlüssel. The messages are in two batches, the Blue and Red series, corresponding to outgoing and incoming messages respectively.
We have developed a new method of breaking Enigma enciphered messages. The
method is using statistical techniques and the
hill climbing search algorithm
to recover the Enigma key. The cryptanalytical method is of the type described
as ‘ciphertext only’ attack and contrary to methods used at Bletchley Park
during the Second World War, does not rely upon probable words, cribs. The
technique allows attacking messages as short as 100 letters long; the shortest
message broken to date is 78 letter long.
An article describing the technical details on how we have attacked and broken these old messages has recently been submitted to Cryptologia, a quarterly journal specializing in cryptology. We have prepared a few selected pages from this forthcoming article which we make available here in PDF format. This will make clearer the scope and complexity of this project.
Excerpts from Breaking German Army Ciphers (PDF format, large file, 1 MB)
Some of these messages are of historical interest and will be published here. The PDF message files contain full ciphertext and Enigma keys for those who are interested in the cryptographical aspects of this work. The complete collection of messages will probably be made available in some form at a later date.
LINKS TO OTHER INFORMATION:
Eavesdropping on Hell: Historical Guide to Western Communicationsby Robert J. Hanyok, NSA.
Intelligence and the Holocaust, 1939–1945
IN THE NEWS:
All rights to the material described on these pages belong to
Geoff Sullivan & Frode Weierud, © April 2005
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