ADFGVX Cipher

Learn how to use the ADFGVX Cipher Tool for secure text encryption and decryption.

Last reviewed: April 2026
Reviewed by , software engineer · last updated April 2026

New to this tool? Click here for instructions

ADFGVX
Plaintext
Ciphertext
Enter plaintext and click Encrypt.

How to Use the ADFGVX Cipher Tool

The ADFGVX Cipher Tool is a free online tool that allows you to encrypt and decrypt text using the WWI ADFGVX fractionating cipher. The process involves two stages: fractionation and transposition. Here's how to use it:

1. Set Your Keys: Enter a Polybius keyword to shuffle the grid and a columnar keyword for transposition. Click 'Apply' to update the 6x6 grid.

  • Enter a Polybius keyword to shuffle the grid.
  • Enter a columnar keyword for transposition.
  • Click 'Apply' to update the grid.

When to Use the ADFGVX Cipher Tool

The ADFGVX Cipher Tool is ideal for situations where you need to securely transmit sensitive information in a field setting. It was designed to be used with pencil and paper, making it practical for quick and secure communication. Use the tool when you need to ensure that your messages are difficult to intercept and decrypt, especially in environments where traditional encryption methods might be impractical.

How It Works

The ADFGVX Cipher Tool works by first converting each plaintext character into a two-letter combination using a 6x6 Polybius square. The grid is then shuffled using a Polybius keyword. The resulting string of ADFGVX symbols is then written into rows under a columnar keyword, and the columns are read out in alphabetical order of the keyword letters. This two-stage process of substitution followed by transposition makes the ADFGVX cipher much stronger than either technique alone, providing a high level of security.

Frequently Asked Questions

The ADFGVX cipher was used by the German Army in WWI. It combined a 6x6 Polybius square (using letters A, D, F, G, V, X instead of numbers) with columnar transposition.
ADFGX (March 1918) used a 5x5 grid for letters only. ADFGVX (June 1918) added V for a 6x6 grid that handled both letters and digits 0-9, increasing the character set to 36 symbols.
French cryptanalyst Georges Painvin broke it in June 1918, working around the clock and losing 30 pounds in the process. His decryption revealed a critical German troop movement that helped stop the Spring Offensive.
A, D, F, G, V, X have very distinct Morse code representations, minimizing the risk that a radio operator would mishear and transcribe the wrong letter when sending or receiving encrypted messages.
The ADFGVX-fractionated string is written into rows under the transposition keyword. Columns are then read out in the alphabetical order of the keyword letters, scrambling the positions of the symbol pairs from the substitution step.