German Field Cipher (1918) - ADFGVX

Description

At first, the text is encoded using a checkerboard cipher. For example, using the substitution key word KEY we may obtain::
A D F G X
A K E Y A B
D C D F G H
F I L M N O
G P Q R S T
X U V W X Z
The text MESSAGE is represented by FF AD GG GG AG DG AD. This is now enciphered using an irregular columnar transposition using a different key. For example, using the transposition key word WORDS we obtain:
W O R D S
5 2 3 1 4
F F A D G
G G G A G
D G A D
This gives the final result as DADFG GAGAG GFGD. The cipher can be used with 25 or 36 letter alphabets. When used with 36 letter alphabets, the checkerboard coordinates are ADFGVX.


To proceed, you may