A Danish Diplomatic Cipher with Table Swtiching in the 17th Century

A diplomatic cipher of Anthon W. v. Haxthausen is printed in Lindenfels (1819), the first book on cryptography in Danish, as I was taught by Franksen (1985), p.28-29. Lindenfels obtained it from "a noble benefactor" (see another article).


(The alphabet includes "Ö" after "Z.")

It is obvious that this is not a mere homophonic substitution cipher (for example, "1" appears on the 1st, 2nd, 3rd, and 4th row). Instead, this includes five different substitution alphabets. Fifteen numbers (9-15 and 30-37) are reserved as indices for indicating which alphabet is used. The alphabet can be switched within a ciphertext by these indices (see the example given).

This was contained, together with a similar cipher, in a sheaf of documents marked on the cover "Chiffres du Gr. Ecuyer Anthon W. v. Haxthausen dans ses mission à différentes Cour." ("Grand Ecuyer" means "Master in Chief of the Horse"). Franksen says Haxthausen was an envoy of Christian IV (1577-1648). But probably he relied on "Christianus quartus" of the example phrase. If the name refers to Anton Wolf von Haxthausen (1647-1694) (Wikipedia in German), who became head stable master in 1680, this must belong to the 1680s or thereabouts.

References:

Ole Immanuel Franksen (1985), Mr. Babbage's Secret

J. B. Lindenfels (1819), Den hemmelige Skriwekonst eller: Chiffrer-og Dechiffrerkonsten [Art of Secret Writing] (Google)



©2021 S.Tomokiyo
First posted on 3 October 2021. Last modified on 3 October 2021.
Articles on Historical Cryptography
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