TheCodeBreakers
lexicon of the KRU code, appeared clearly in the trinumeral message as
the repeated 245s and 659s. With these four points as anchors, Berthold
could set up the following equivalencies:
845 422 373 792 240 245 068 652 781 245 659 659 504 An [?] Bn. 2
h i r sch w i t t e
A staff airplane sped his result to the British cryptanalytic bureau,
and Berthold telegraphed it in a special code-breakers' code to the
French. It was a Rosetta Stone for a new forward code called the
Schliisselheft. The three bureaus cooperated closely, but it was largely
due to a French genius that within two days they had neutralized the
Schliisselheft superencipherment and dismembered much of the lexicon.
By March 21, when the expected German blow fell, Allied cryptanalysts
were reading Schliisselheft messages better than the German code clerks
themselves. Theoretically no important information was supposed to be
carried in it, because it was intended only for low-level, . front-line
communications
annaabi.ee 
