Conference article

The Auxiliary Devices of OKW/Chi

Carola Dahlke
Deutsches Museum, Germany

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Published in: Proceedings of the 3rd International Conference on Historical Cryptology HistoCrypt 2020

Linköping Electronic Conference Proceedings 171:9, p. 60-69

NEALT Proceedings Series 44:9, p. 60-69

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Published: 2020-05-19

ISBN: 978-91-7929-827-2

ISSN: 1650-3686 (print), 1650-3740 (online)


Between 1942 and 1945, section IVb of OWK/Chi designed mechanical and electro-mechanical devices to statistically evaluate intercepted encrypted messages. By the help of TICOM protocols and a never published dissertation draft written by Willi Jensen in 1955, an overview of the cryptanalytic devices is given. Most probably all the equipment was destroyed at the end of the war. Only dredged-up remnants of one type of equipment could be recovered by German divers.


OKW/Chi; rapid analytic machinery; TICOM; German cryptanalysis; WWII


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