Cipher Tools (Caesar, XOR, Vigenère)
Encode and decode classic ciphers — Caesar, ROT13, XOR, Vigenère and Atbash — entirely in your browser. Useful for CTFs, puzzles and analysis.
Apply a Caesar shift of 3
Encrypt a short phrase with a Caesar shift of three to see each letter moved down the alphabet.
The output updates live as you type — there’s no button. Caesar is affine; ROT13 is just a fixed shift of 13.
FAQ
Are these ciphers secure?
No. Caesar, XOR and Vigenère are classical ciphers that can be broken in seconds by hand or with simple frequency analysis. They’re for education, CTFs and puzzles — use AES for anything real.
What is the difference between Caesar and Vigenère?
Caesar shifts every letter by the same amount. Vigenère shifts each letter by a different amount determined by a keyword, which is stronger but still not modern-cipher secure.
How does the XOR cipher work?
Each character’s byte is XORed with the next byte of the key, cycling through the key. It’s symmetric — applying the same key again decrypts. Reusing a key makes it trivially breakable.
What is Atbash?
Atbash swaps each letter with its alphabet mirror (A↔Z, B↔Y). It’s a substitution cipher with no key — handy as a quick obfuscation but no security value.