🔐 Cryptography & Substitution Ciphers
ROT13 & Caesar Cipher Converter
Encode and decode Caesar shift ciphers ($C = (P + K) \bmod 26$), $\text{ROT13}$, $\text{ROT5}$, and $\text{ROT47}$ with a real-time 25-key brute force decipher table.
💬 Standard ROT13
🏛️ Julius Caesar Classic (Shift 3)
🕵️ Secret Message (Shift 7)
Original Input Text
Encrypted / Decrypted Output
ROT13 Invertible
All 25 Caesar Shift Possibilities (Brute Force Decipher):
| Shift | Deciphered Text Candidate |
|---|
How the Caesar Cipher & ROT13 Work
The Caesar cipher is one of the oldest known encryption techniques, named after Julius Caesar who used a shift of $3$ to protect military messages:
- Encryption Formula: $$E(x) = (x + k) \bmod 26$$
- Decryption Formula: $$D(x) = (x - k) \bmod 26$$
- ROT13 Symmetry: Because $26 / 2 = 13$, shifting by 13 twice returns the initial text ($13 + 13 \equiv 0 \pmod{26}$). ROT13 is widely used in forums to obscure movie spoilers, puzzle solutions, and offensive jokes.