Cipher Playground
Encode & decode classic ciphers: Caesar, ROT13, Atbash, Vigenère, A1Z26, Morse, Binary, Hex, Rail Fence, Bacon. Live preview, deep-link, copy, history.
About this tool
Classic ciphers are the substitution and transposition schemes taught in every introductory cryptography course: Caesar shifts each letter by a fixed amount (ROT13 is the special case where the shift is 13, which is its own inverse), Atbash reverses the alphabet (A↔Z, B↔Y), Vigenère uses a repeating keyword to vary the shift per letter, and Rail Fence scrambles the order of letters instead of replacing them.
Alongside these letter-based ciphers the playground also handles simple encodings that turn text into other symbols: A1Z26 (A=1, B=2, …), Morse code, binary and hex representations of each character's byte, and Bacon's cipher (A/B five-letter groups). Each one is fully reversible, so you can decode just as easily as encode.
Example: Hello in ROT13 → Uryyb; in Caesar with shift 3 → Khoor; in Morse → .... . .-.. .-.. ---. They are useful for puzzles, CTF challenges, and understanding how the field evolved before modern encryption.
FAQ
Are these ciphers secure? ›
No. Every cipher here can be broken by hand or with simple frequency analysis. They are historical and educational, not for protecting real secrets — use AES or another modern cipher for that.
What is the difference between Caesar and ROT13? ›
Caesar shifts by any amount you choose; ROT13 is the specific case where the shift is 13. Because the alphabet has 26 letters, applying ROT13 twice returns the original text, which made it popular for hiding spoilers in Usenet posts.
How does Vigenère use a keyword? ›
Each letter of the keyword tells the cipher how far to shift the corresponding letter of the message, cycling the keyword as needed. With the key "KEY" and the message "HELLO", the shifts are K(10), E(4), Y(24) applied repeatedly.
Why does Morse code for some characters look identical? ›
Morse assigns short codes to common letters (E is one dot) and longer codes to rare ones, so on its own the dots and dashes are ambiguous. Real Morse relies on the gaps between letters; in plain text we separate letters with spaces to remove the ambiguity.
Is there a dedicated Morse Code tool? ›
Yes — for audio playback of Morse code and a dedicated encode/decode workflow, use our Morse Code Converter. The Cipher Playground includes Morse as a text-only encoding alongside nine other ciphers.