Caesar · Vigenère · Atbash · Rail fence · Affine
🔐 Classical Ciphers
Encode and decode text with the classic pen-and-paper ciphers — Caesar shift, Vigenère keyword, Atbash, Rail fence and Affine — both ways in real time. Then break a monoalphabetic cipher yourself with a live letter-frequency chart and an automatic Caesar cracker.
Input
Result
Letter frequency of the result
Result
Typical English (‑‑‑) / Vietnamese (···)
Auto-crack a Caesar cipher
Treats the input above as ciphertext and ranks all 26 shifts by how English-like each looks. Click a shift to apply it.
These ciphers work on the 26 Latin letters A–Z; digits, spaces, punctuation and Vietnamese accented letters pass through unchanged. Caesar and Atbash are monoalphabetic — a frequency chart alone can break them. Vigenère resists that unless you know the key length. None of these is secure by modern standards: treat them as puzzles and history, not protection.