Text Cipher Tool

Encode or decode with Caesar (0-25 shift slider), ROT13, Atbash, reverse, Base64 and Hex. The result updates instantly as you type.

Everything is processed locally in your browser. Your text never leaves your device.

How It Works

Each cipher is a small text transformation defined by simple rules: Caesar shifts every letter, Atbash mirrors them across the alphabet, and Base64 and Hex rewrite bytes as text. The tool applies the chosen transformation on every keystroke and shows the result instantly — all without leaving your device.

Encrypt and decrypt
With Caesar you pick a 0–25 shift and a direction: encrypt shifts letters forward, decrypt brings them back. ROT13, Atbash and reverse are symmetric — the same operation encodes and decodes, so the direction does not matter.
Base64 and Hex with UTF-8
Before encoding, your text is converted to UTF-8 bytes with the browser's TextEncoder; after decoding, the bytes turn back into text with TextDecoder. That is why accents, emojis and Asian scripts survive intact instead of coming out as broken characters.
Browser-only
All six ciphers fit in a few lines of JavaScript running locally. There is no server, no network requests and no storage: reloading the page leaves the tool blank.

Frequently Asked Questions

Is Caesar cipher a real encryption?

It is a substitution cipher, not modern encryption: every letter is shifted by the same amount, so only 25 possible keys exist and a frequency analysis breaks it in minutes. ROT13 and Atbash are fixed variants of the same idea. The tool is useful for obfuscation, puzzles and learning — not for protecting real secrets.

How does Base64 handle non-ASCII text?

The tool first encodes your text to UTF-8 bytes with the browser's TextEncoder, then Base64-encodes those bytes. Decoding does the reverse with TextDecoder, so accented characters, emojis and CJK text round-trip correctly instead of being mangled.

What happens if I paste invalid Base64 or Hex while decoding?

The output area shows an error message instead of garbage. Base64 input must have a length that is a multiple of four (padding with = is accepted), and Hex input must be an even-length string of 0-9 and a-f characters.

Is my text uploaded or stored anywhere?

No. Every cipher is a few lines of JavaScript running in your browser. Nothing is sent over the network, nothing is saved to a server, and reloading the page clears the tool.

Do I need an internet connection?

No. The page bundles all the code it needs, so once it has loaded the tool works fully offline. No accounts, no analytics and no tracking of the text you process.