Deciphering German diplomatic and naval attaché messages from 1900-1915
George Lasry, Ingo Niebel, Torbjörn Andersson · Cryptologia · 2020
In World War One (WW I), the German diplomatic services and the Imperial Navy employed codebooks as the primary means for encoding confidential communications over telegraph and radio channels. The Entente cryptographic services were able to reconstruct most of those codebooks, to obtain copies of others, and to overcome various enhancements introduced by the Germans.A collection of diplomatic and naval attaché cryptograms from and to the German consulate in Genoa, dating from the late 19th Century to 1915, has been preserved and is held in German archives.11 Politisches Archiv des Auswärtigen Amtes, RAV Genua - Records from the German consulate general in Genoa (PAAA – RAV Genua).In this article, the authors describe the process of identifying the encoding methods, of reconstructing diplomatic codebooks, and of recovering the superencipherment applied to the German Navy’s Verkehrsbuch. The vast majority of the messages can now be read in clear. The authors also provide the historical context for the messages, which shed new light on the impact of the mobilization and war declarations on the Genoa consulate, its role in gathering naval intelligence, and in assisting the Goeben and Breslau warships in their escape to the Dardanelles in August 1914.22 An early version of this paper with preliminary results was presented at HistoCrypt 2018 (Lasry 2018 Lasry, G. 2018. Invited talk-special session on Arne Beurling: Modern codebreaking of T52. In Proceedings of the 1st International Conference on Historical Cryptology HistoCrypt 2018, number 149. Linköping University Electronic Press. [Google Scholar]). The current version includes an in-depth historical analysis, as well as a detailed description of codebook 18102.