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RC4 Stream Cipher - Encrypt & Decrypt Online
Free online RC4 stream cipher encryption tool. Encrypt and decrypt text with a custom symmetric key. Legacy cipher for educational use and compatibility testing.
How to Use RC4 Encrypt/Decrypt
Quick Start Guide
1
Enter a secret key in the Key field - this is used for both encryption and decryption
2
Type or paste your text into the input area to encrypt
3
Click Encrypt to convert your text using the RC4 stream cipher, or Decrypt to reverse it
4
Copy the result - use the same key on any other RC4 tool to decrypt your data
Frequently Asked Questions
RC4 is a stream cipher that encrypts data one byte at a time using a variable-length key. It was widely used in SSL/TLS and WEP protocols due to its speed and simplicity. While no longer recommended for new systems, it remains useful for legacy compatibility and learning about stream ciphers.
RC4 has known vulnerabilities when used with certain key patterns or when the same key encrypts multiple messages. For production systems, modern algorithms like AES-GCM or ChaCha20 are recommended. This tool is intended for educational use, legacy system compatibility, and non-critical data.
No. RC4 is a symmetric cipher, meaning the same key is required for both encryption and decryption. Without the correct key, RC4-encrypted data cannot be recovered.
No. All encryption and decryption happens entirely in your browser using JavaScript. Your text and key never leave your device.
Still have questions? Check out our other tools or contact us for support.