Web Tools
ROT13 / Caesar Cipher
Encrypt and decrypt text using the Caesar cipher with configurable shift (1-25). Includes ROT13 preset, brute-force decoder showing all 25 shifts, and letter statistics. Runs entirely in your browser — your data never leaves your machine.
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Published May 30, 2026
All interactive tools run entirely in your browser. Your data never leaves your device.
How It Works
Enter text and select a shift value (1-25) to encrypt or decrypt using the Caesar cipher. Non-alphabetic characters (numbers, punctuation, spaces) are preserved unchanged. Use the brute-force feature to try all 25 possible shifts at once.
Features
- Configurable shift: slider and preset buttons for quick selection (ROT1, ROT5, ROT13, ROT18, ROT25)
- Encrypt and decrypt: bidirectional operation
- Brute-force decoder: shows all 25 possible decryptions at once
- Case preserving: maintains uppercase and lowercase
- Non-alpha passthrough: numbers, punctuation, and symbols are unchanged
- Statistics: input length, letters shifted, shift value
- 5 examples: Hello World, classic pangram, military message, mixed content, full alphabet
- Private: runs entirely in the browser — no data transmitted
Use Cases
- Encoding simple text messages (ROT13)
- Learning about classical cryptography
- CTF (Capture The Flag) challenges
- Decoding ROT13-encoded text from forums and Usenet
- Brute-forcing unknown Caesar cipher shifts