Caesar Cipher client-side
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How to use Caesar Cipher

The Caesar cipher shifts every letter of the text by a fixed number of positions in the alphabet: with a shift of 3, A becomes D, B becomes E, and so on. Pick your shift from 0 to 25 to encrypt or decrypt, or use the ROT13 (shift of 13, its own inverse) and ROT47 (over printable ASCII, to include digits and symbols) presets. The brute-force mode shows all 26 possible shifts at once: when you don't know the key, just scan the list and spot the readable line. It's the go-to method to solve a Caesar-encrypted puzzle. Everything is computed in your browser, with no data ever sent.

Caesar shift, ROT13, ROT47 and automatic brute-force.

CésarROT13DécalageCryptographieEncryption

How to use Caesar Cipher

The Caesar cipher shifts every letter of the text by a fixed number of positions in the alphabet: with a shift of 3, A becomes D, B becomes E, and so on. Pick your shift from 0 to 25 to encrypt or decrypt, or use the ROT13 (shift of 13, its own inverse) and ROT47 (over printable ASCII, to include digits and symbols) presets. The brute-force mode shows all 26 possible shifts at once: when you don't know the key, just scan the list and spot the readable line. It's the go-to method to solve a Caesar-encrypted puzzle. Everything is computed in your browser, with no data ever sent.

Frequently asked questions

What is ROT13?

A Caesar cipher with a shift of 13. Since the alphabet has 26 letters, applying ROT13 twice returns the original text: encrypting and decrypting are the same operation.

How do I crack a Caesar without the key?

Use the brute-force mode: it lists all 26 possible shifts. Exactly one line will be readable text — that's the decrypted message.

Does ROT47 cipher digits and symbols?

Yes. Unlike Caesar/ROT13 which only touch letters, ROT47 shifts all 94 printable ASCII characters, so digits and punctuation too.