RC4 Cipher
RC4 stream cipher.
🌊RC4 Cipher
All processing happens locallyWhat this tool does
RC4 Cipher is a RC4 Cipher that computes locally and shows the result instantly., everything runs inside your browser, so neither the key nor the plaintext ever leaves your device.
Copy the result directly. Keys are never persisted anywhere, so save them yourself.
How to use it
- Paste or type your content into the input field at the top, or press the sample button to load demo data.
- Adjust the options below the input, such as output format, separators, letter case or precision.
- Press the main button to run the conversion. Results appear instantly in the output panel without a page reload.
- When the result looks right, use the copy button in the corner, or download it as a local file.
Tips and notes
Clean up stray spaces and line breaks before pasting for more accurate results.
FAQ
Not for new systems. Its keystream has statistical biases (well documented in the literature) and TLS has banned it. Use it only for legacy data or protocols.
No. RC4 only seeds its state from the key, so the same key and plaintext always give the same ciphertext, which is one reason it is unsafe.
Anywhere from 1 to 256 bytes. At least 16 bytes is advisable, but RC4 is still not recommended for production encryption.
Yes. The tool is completely free with no usage limits, and you never need an account or a sign-in.
No. All processing runs locally in your browser, so the input never reaches a server and is never logged or stored.
Yes. The layout is mobile-first, so inputs and buttons stay comfortable on phones and tablets in both orientations.
Yes. A copy button in the output panel puts the result on your clipboard, and you can also download it as a text file.