RHV Part 2 - The RHV message key


By Michael Hörenberg

Now we have to determine the RHV message key. We need the "RHV Tauschtafelfolge" (RHV bigram substitution table sequence) and the so called "RHV Zahlenreihe" (RHV number sequence).

RHV Zahlenreihe: Determines the length of the transposition box and the way we have to do the transposition.
RHV Tauschtafelfolge: Determines the order we have to use 4 bigram substitution tables from a set of e.g. 25.

This two components of the message key are determined by the "Schlüsselkenngruppe" and "Verfahrenkenngruppe". See also Part 1 of the RHV procedure. We need the "laufende Nummer" (lfde.Nr.) of the "Kenngruppen" --> lfde.Nr. means "running number" or the row in the K-Book. From Part 1 of the procedure we know:

lfde.Nr. Schlüsselkenngruppe:  6
lfde.Nr. Verfahrenkenngruppe: 13

Bild "Tauschtafelweiser"
table sequence selection chartWith this information we can look up the "Tauschtafelfolge" in the RHV Tauschtafelweiser (table sequence selection chart).

We find:
Tauschtafelfolge: 11 6 9 16 (cross-over point of the 2 axxis --> lfde.Nr. "Schlüsselkenngruppe" and "Verfahrenkenngruppe").

The first table (11) is the so called "Einsatzstelle" and determines the "Zahlenreihe" (number sequence) in the RHV "Zahlenreihentafel" (number sequence selection chart).

Bild "Zahlenreihentafel"
number sequence selection chartWith the "Einsatzstelle" we find the correct "Zahlenreihe" (number sequence) in the RHV "Zahlenreihentafel" (number sequence selection chart)

"Zahlenreihe" 11 is: 7 14 4 8 3 9 6 13 2 10 5 11 1 15 12

With this information we can create the "Kastenwürfel" (transposition box).

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