ADFGVX is a German field cipher from World War I. This historical cipher combines fractionation in a keyed 6×6 Polybius square with columnar transposition, making it substantially more complex than either stage on its own.
To encrypt text with the ADFGVX cipher, enter a message, a square key, and a transposition key. The square key places the 26 English letters and digits 0–9 into the 6×6 grid. Its rows and columns are labelled A, D, F, G, V, and X, letters selected because their Morse-code signals are easy to distinguish. Each plaintext character is replaced by its row-and-column pair; the transposition key then changes the order of those ADFGVX labels to create the ciphertext.
To decrypt, use exactly the same two keys and paste the ciphertext made from A, D, F, G, V, and X. The tool reverses the columnar transposition first, then reads every label pair back through the keyed Polybius square. Spaces and punctuation are not encrypted, so the recovered result contains the supported letters and digits only. This online ADFGVX cipher is useful for learning classical cryptography, historical study, and puzzles; it is not suitable for protecting modern sensitive data.