The Germans believed ADFGX was unbreakable when they introduced it during World War I — and it took French cryptanalyst Georges Painvin weeks of painstaking work to prove them wrong, providing intelligence credited with helping halt a major 1918 offensive.
What Is the ADFGX Cipher Tool?
ADFGX is a two-stage cipher: first, a keyword mixes the alphabet into a 5x5 grid (I and J share a cell) labeled A/D/F/G/X on both axes, and every plaintext letter becomes a row/column pair from that grid. Second, the resulting stream of letter-pairs is scrambled using a columnar transposition driven by a separate keyword — the same technique used in the site’s Caesar Box cipher tool, but applied to fractionated letters instead of the raw message.
How to Use It
- Open the tool at /tools/adfgx-cipher.
- Type your message into the text field.
- Set a Polybius square keyword to mix the grid, and a separate transposition keyword.
- Click Encrypt or Decrypt, then copy the result.
Key Features
- Two independent keywords — one for the grid, one for the transposition — matching the historical design exactly.
- Live-rendered Polybius square, so you can see exactly how your grid keyword mixed the alphabet.
- Verified round-trip encryption/decryption, confirmed to recover the original message exactly.
- Fully client-side, nothing ever leaves your browser.
When to Use This Tool
- World War I cryptography history, studying one of the most famous field ciphers ever broken by Allied codebreakers.
- Cryptography coursework covering fractionating ciphers combined with transposition.
- Puzzle design needing a cipher with real historical stakes attached to it.
Try It Now
Open ADFGX Cipher directly, or press ⌘K and type the tool name from anywhere on the site.
Part of the Security & Crypto collection on WebdevToolbox — free, browser-based developer tools with no login required.