Caesar Cipher - Encrypt, Decrypt & Brute Force Any Shift
Caesar Cipher
Shift letters to encrypt, decrypt, or crack a message without the key
Any Shift, Live
Pick a shift from 0 to 25 with the box or the slider and the result updates as you type.
Brute Force View
All 26 possible decryptions are listed at once. Spot the readable one, then click Use to select it.
Shift Detection
Compares letter frequencies with English to suggest the most likely shift. It needs a reasonable amount of English text.
Full Privacy
Everything runs in your browser. Your message is never uploaded.
About the Caesar Cipher
The Caesar cipher is named after Julius Caesar, who reportedly shifted letters by three places to protect military messages. With a shift of 3, A becomes D, B becomes E, and so on, wrapping around from Z back to A. Decrypting simply shifts the same distance the other way.
It offers no real security: there are only 25 useful keys, so anyone can try them all in a second, as the brute-force table shows. Today it is a teaching tool and a puzzle staple, not a way to protect anything sensitive. Only the letters A to Z are shifted; case, digits, punctuation and accented letters are left unchanged.
Key Takeaways
- Educational: Ideal for learning classical cryptography and solving puzzles.
- Reversible: Encrypting with shift N and decrypting with N always returns the original.
- Related tool: ROT13 is the special case with a shift of 13, where encrypting and decrypting are the same operation.