TheCodeBreakers
left with the hypothesis that the checkerboard substitution had been
subjected to a transposition. On this basis he began to work.
Nothing happened. The traffic was too light for him even to determine
by frequency counts whether the checkerboard key changed each day,
and without this basic information he did not dare to amalgamate the
cryptograms of successive days for a concerted assault. Colonel Francois
Cartier, head of the Bureau du Chiffre, looked on over his shoulder as he
braided and unbraided the letters and . mused sadly, "Poor Painvin. This
time I don't think you'll get it." Painvin, goaded, worked harder than
before. Meanwhile, Berthold achieved his Schliisselheft entry and
Painvin, shifting temporarily to that more fruitful field, completed it. But
the enciphered code, used only for trench communications, provided no
strategic insights. These would come, if they were to come at all, through
solution of the ADFGX, which direction-finding showed was carrying
annaabi.ee 
