ADFGVX cipher decoder and encoder

The ADFGVX cipher was used by the German Army during World War I. It was invented by Lieutenant Fritz Nebel and is a fractionating transposition cipher which combines a Polybius square with a columnar transposition. The name comes from the six possible letters used: A, D, F, G, V and X. These particular letters were chosen because they are very different from each other in Morse code, which reduced the risk of telegraphy operator errors. It was an extension of the earlier ADFGX cipher.

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ADFGVX cipher tool


Polybius square


Transposition grid



  • The ADFGVX cipher is a combination of a Polybius square and a columnar transposition cipher.
  • It is simple enough to be possible to carry out by hand.
  • It can encrypt 36 characters. In addition to the 26 letters in the English alphabet, it can also encrypt digits (0-9).
  • During World War I, the Germans believed the cipher was unbreakable. It was however broken by a French cryptanalyst in 1918. As a direct result, the French army discovered where the Germans were planning to attack.

Sample text


The ciphertext above represents "SECRET MESSAGE" encrypted using the keys CIPHER and TOOL.