Free tool · for puzzles, CTFs and class
Classic cipher encoder & decoder
Ten classic ciphers in one place, from Caesar and Vigenère to Morse code and Bacon. Type a message to encode it, or paste a coded clue to solve it, and the result updates as you type. Each method has a short explanation of how it works. Great for escape-room clues, CTF warm-ups and cryptography homework.
How to use the tool
- 1
Choose a method
Pick Caesar, ROT13, ROT47, Vigenère, Atbash, Affine, Rail Fence, Morse, A1Z26 or Bacon.
- 2
Set the key
Enter the shift, keyword, a and b values or number of rails. Methods without a key skip this step.
- 3
Encode or decode
Choose a direction and type. Use the swap button to feed the result back in and check that it decodes.
- 4
Stuck on a clue?
For Caesar, the brute-force panel shows all 25 shifts and marks the one that looks most like English.
QRScanKaro
Planning a treasure hunt?
Print each clue as a QR code: players scan it to reveal the next coded message. Make QR codes with your colours and logo, free.
Make a clue QR →Frequently asked questions
Can I use these ciphers to keep a message secret?
No. They are great for learning and puzzles, but all of them can be broken in seconds, often by hand. For a real secret, use the Text Encryption tool, which uses AES with a password.
How do I know which cipher a puzzle uses?
Look at the symbols. Only dots and dashes means Morse. Groups of five A/B letters means Bacon. Numbers from 1 to 26 suggest A1Z26. Normal letters in odd order may be Rail Fence, and scrambled letters in normal word shapes are usually Caesar, Atbash or Vigenère.
Does it keep capital letters and punctuation?
The letter ciphers (Caesar, ROT13, Vigenère, Atbash, Affine) keep upper and lower case and leave digits, spaces and punctuation as they are. Morse, A1Z26 and Bacon decode to capital letters. Rail Fence moves every character, spaces included.
Can it play Morse code as sound?
Yes. Choose Morse and press Play to hear the message as beeps. You can set the speed from 5 to 40 words per minute and stop at any time.
Is anything I type sent to a server?
No. Every cipher runs in your browser, and your messages are never uploaded or saved.
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