Scienceblogs.de, a German science blogging portal, includes a relatively famous list of 50 unsolved ciphers , which range from cryptograms published by serial killers to the famous Voynich manuscript .

Among these ciphers is a set of German radio messages from World War I that were encoded using the ADFGVX method.

This method is illustrated by the following example using the word “HOUSE” as the key:

A D F G V X A H O U S E A D B C D F G I F J K L M N P G Q R T V W X V Y Z 0 1 2 3 X 4 5 6 7 8 9

As you can see, ADFGVX is used both horizontally and vertically to give each “cell” in the table a value. For example, in this text, “AA” corresponds to the letter H, “AD” corresponds to the letter O, “DA” corresponds to the letter B, and so on.…