CcConvertCase

Caesar Cipher Encryption

Encrypt or decrypt text using the Caesar cipher. Adjust the shift (1–25), use ROT13 with one click, or brute-force all 25 possible shifts at once.

Characters: 0 | Words: 0 | Lines: 0

113 (ROT13)25

EXAMPLE — ROT3 (classic Caesar)

Input:   Hello World

ROT3:   Khoor Zruog

About the Caesar Cipher

The Caesar cipher is a substitution cipher in which each letter is replaced by a letter a fixed number of positions further along the alphabet. Julius Caesar reportedly used a shift of 3 to protect military communications.

Encryption example (shift 3)

  • A → D, B → E, C → F …
  • "Hello" → "Khoor"
  • To decrypt: shift by −3 (or equivalently +23)

Is it secure?

No. With only 25 possible keys, it is trivially broken by brute force or frequency analysis. It is used today for educational purposes, puzzles, and CTF (Capture The Flag) competitions.