Decrypting Text - code breaking software
The Colossus at Bletchley

ADFGVX cipher decryption

This cipher is obvious by the composition of its ciphertext - only 6 letters ADFGVX and it isn't easy to decipher. It uses a 6 * 6 grid of characters to substitute for the 26 letters and 10 numbers (optional) of the plaintext. The letters A D F G V X are used to create 36 double chars eg. AD AF VV FX and so forth. By referring to this grid the plaintext is converted into a set of these characters giving a stage 1 ciphertext. This cipheretext is then transposed by using a keyword that is written in the first row of a new grid with the ciphertext arranged accordingly within. The columns of the grid are then arranged so that the keyword letters are now in alphabetic order which gives the final ciphertext
This program assumes that the ciphertext has already been transposed (use the transposition cipher to do this) and ready for the final letter substitution. You will also need to do a frequency analysis so that you have some ideas as to what letters to put in the grid.

 

Enter your ciphertext below
Enter your letters
Note that the left column comes first followed by the row. DF is the name for the coloured cell.
A
D
F
G
V
X
A
D
F
G
V
X