Caesar Cipher
Encrypt, decrypt, and brute-force Caesar cipher text with real-time output and adjustable shift values
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Ciphertext
Caesar Cipher
Encrypt, decrypt, and brute-force Caesar cipher text with real-time output and adjustable shift values
Features
- Encrypt and decrypt text with adjustable shift values from 0 to 25
- Real-time output updates as you type — no button clicks needed
- Brute-force mode shows all 26 possible decryptions at once
- Options to preserve letter case and shift numeric digits
- Swap button to quickly reverse encrypt/decrypt operations
- 100% client-side — no data leaves your browser
How to use
- Choose Encrypt or Decrypt mode using the toggle buttons.
- Set the shift value using the slider or number input (0-25).
- Type or paste your text in the input area — the output updates in real time.
- Use the Brute Force button to see all 26 possible decryptions.
- Click Copy to copy the output or any brute-force result to your clipboard.
Tips & Best Practices
- ROT13 is just a Caesar cipher with a shift of 13 — it is its own inverse.
- Use brute force to quickly crack any Caesar-encoded text.
- The Swap button lets you verify your work by reversing the operation.
- Enable 'Shift numbers' to also rotate digits 0-9 along with letters.
- Bookmark this page to use it offline after the first load.
FAQ
What is a Caesar cipher?
A Caesar cipher is one of the oldest known encryption methods. It works by shifting each letter in the alphabet by a fixed number of positions. For example, with a shift of 3, A becomes D, B becomes E, and so on. It is named after Julius Caesar, who reportedly used it for military correspondence.
How does the shift value work?
The shift value determines how many positions each letter moves in the alphabet. A shift of 1 turns A into B, a shift of 13 turns A into N (this is ROT13), and a shift of 25 turns A into Z. A shift of 0 or 26 returns the original text.
What is the brute-force feature?
Since there are only 26 possible shifts (0-25), the brute-force feature shows the result of applying every possible shift to your input text. This is useful for cracking a Caesar cipher when you do not know the original shift value.
Is my data private?
Yes. All encryption and decryption happens entirely in your browser using JavaScript. No data is sent to any server or third party.
Can I use this for real security?
No. The Caesar cipher is a simple substitution cipher that can be broken trivially by brute force (only 26 keys). It is useful for learning about cryptography, puzzles, and CTF challenges, but not for protecting sensitive data.