Caesar Cipher

Encrypt or decrypt text with a Caesar shift.

Shift

Plaintext

Note: The Caesar cipher shifts each letter by a fixed number of positions in the alphabet. "Shift 3" turns "HELLO" into "KHOOR". It is one of the oldest and simplest ciphers and is trivially breakable.

What Is a Caesar Cipher?

The Caesar Cipher tool shifts every letter by a fixed number of positions in the alphabet. It is one of the oldest known ciphers, used by Julius Caesar. A shift of 3 turns 'HELLO' into 'KHOOR'.

How to Use This Caesar Cipher

1
Enter ShiftType a number of positions to shift (e.g. 3).
2
Enter TextType the plaintext or ciphertext.
3
Choose DirectionClick Encrypt or Decrypt to apply the shift.

Frequently Asked Questions

Try all 25 possible shifts. With a Caesar cipher, one of them will produce readable text — this is why it is so easy to break.

Yes. Only letters are shifted; case is preserved and non-letter characters (spaces, digits, punctuation) pass through unchanged.

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