Caesar Cipher
Encrypt and decrypt text with letter shifting
Caesar Cipher Online - Encrypt and Decrypt
The Caesar cipher is one of the oldest and simplest substitution ciphers in the history of cryptography. It is named after Julius Caesar, who used it to encrypt military correspondence. Each letter in the text is shifted by a fixed number of positions in the alphabet.
How does the Caesar cipher work?
The Caesar cipher shifts every letter in the text by a fixed number of positions in the alphabet. For example with a shift of 3: A→D, B→E, C→F, etc. Decryption is shifting in the opposite direction.
Encryption examples
Shift +1
ABC → BCD
Shift +3 (Caesar)
ABC → DEF
Shift +13 (ROT13)
ABC → NOP
Shift +25
ABC → ZAB
What is the Caesar cipher used for?
- Education - Learning cryptography and algorithms
- Puzzles and games - Creating secret messages
- Geocaching - Encrypting clues in outdoor games
- Escape rooms - Logic puzzle element
- History - Understanding the roots of cryptography
What is ROT13?
ROT13 is a special case of the Caesar cipher with a shift of 13. Because the Latin alphabet has 26 letters, applying ROT13 twice restores the original text. ROT13 is often used online to hide spoilers and jokes.
Frequently asked questions
Is the Caesar cipher secure?
No, the Caesar cipher is easy to break - there are only 25 possible shifts. It's for learning cryptography, not protecting data.
Are accented characters supported?
Yes, our cipher supports accented characters (é, ñ, ü, etc.) where the alphabet allows.