Codes and ciphers

• Morse code: Dots and dashes, by ear.
• NATO alphabet: Alfa, Bravo, Charlie.
• Caesar shift: Every letter moves three.
• ROT13: Caesar, halfway round.
• Atbash: A for Z, B for Y.
• Tap code: Knocks through a wall.
• Pigpen: Letters drawn as pens.
• Braille: Six dots you can feel.
• Polybius square: Every letter is two numbers.
• Flag semaphore: Two flags, eight positions.
• Keyword cipher: A secret word reshuffles the alphabet.
• Vigenère: A keyword that keeps shifting.
• Rail fence: Letters zigzag between rails.
• Substitution: Any letter for any letter.
• Book cipher: Page, line, word.

Got a coded message?

If a friend sent you a message from Covert Mail or from one of these pages, paste it here to read it.

For learning, not for secrets

These are classical codes. Every one of them can be broken, and most can be broken by hand, which is what makes them good to learn on. Do not use them to protect anything that matters.