How to decipher an ADFGVX cipher?
As you must know, ADFGVX is a German cipher from World War I. It was broken by the French (Painvin) during that war, but not without a major effort, and only on certain days.

It uses fractionation and a Polybius square, followed by a columnar transposition based on a keyword.

In Milton F. Friedman's Military Cryptanalysis, Part IV, pp. 103-149, he goes into detail about how to break this cipher.

There is also a useful paper from 1984, Konheim, A. G. (n.d.). Cryptanalysis of Adfgvx Encipherment Systems. Lecture Notes in Computer Science, 339–341. doi:10.1007/3-540-39568-7_26 (an extended abstract)

Konheim presents a four-step cryptanalytic technique to break ADFGVX.


Determine which column vectors are adjacent in the array.
Determine the relative order of the pairs of column vectors.
Recover the substitution.
Recover the transposition order of the columns in the array.


One thing that could be looked at first is this: perhaps the Polybius square is not a mixed alphabet after all, but alphabetical.