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ADFGVX was a real field cipher used by the German army in World War I, combining a 6x6 grid substitution (covering all 26 letters and 10 digits) with a second, separate columnar transposition step for extra security.
This tool encrypts or decrypts text using ADFGVX with two keywords you choose: one for the grid, one for the transposition.
How it works
The 26 letters and 10 digits (36 characters total) fill a 6x6 grid keyed by your first keyword, with rows and columns labeled A, D, F, G, V, and X (letters chosen because they sound very different in Morse code, reducing transmission errors). Each character of your text is replaced with its row and column letters, then the entire resulting letter sequence is columnar-transposed — reordered into columns based on the alphabetical order of your second keyword's letters. Decryption reverses both steps in order.
- Enter mode.
- Enter text.
- Enter grid Keyword.
- Enter transposition Keyword.
- Click Calculate to see your results.
Examples
Grid keyword "PLAYFAIR", transposition keyword "GERMAN"
"ATTACKAT1200PM" (including digits) encrypts to an ADFGVX letter sequence — note this cipher explicitly supports digits, unlike most classical letter-only ciphers.
Who should use it
- Puzzle and escape-room style word games with historical context.
- Teaching how combining substitution and transposition strengthens a cipher.
Industry applications
- Cryptography education and military history
- Games and puzzles
Advantages
- Combines two different cipher techniques (substitution and transposition) in one cipher.
- Supports digits as well as letters, unlike most classical ciphers.
- Genuine historical significance from real WWI battlefield use.
Limitations
- More involved to work through by hand than a single-step cipher.
- No real security against modern cryptanalysis, despite its historical strength.
Common mistakes to avoid
- Mixing up the two keywords, or using a different pair for decryption than encryption — both must match exactly.
- Forgetting that ADFGVX handles digits as well as letters, unlike most of the other classical ciphers on this site.
Best practices
- Use ADFGVX for puzzles or to study how combining substitution with transposition made classical ciphers meaningfully stronger.
Tips
- If your result looks wrong, decrypt in two mental steps: first undo the transposition (needs the transposition keyword), then undo the substitution (needs the grid keyword) — checking each stage separately makes mistakes easier to spot.