RC4 cipher
Encrypt or decrypt text with the RC4 stream cipher (symmetric key).
How it works
RC4 is a stream cipher: it generates a pseudo-random sequence of bytes (the "keystream") from a key, then combines that sequence with the text using an XOR. Running the same operation with the same key decrypts the data, because XOR is reversible. This tool is useful for understanding or experimenting with RC4 in an educational context, or for working with older systems that still use it.
Is RC4 safe to use today?
No. RC4 has been considered cryptographically broken for several years (statistical biases in the keystream, practical attacks against WEP and TLS) and has been removed from modern standards. This tool is provided for educational purposes and for compatibility with legacy formats, not to protect sensitive data.
Why is the encrypted result displayed in hexadecimal?
RC4 produces raw bytes that aren't necessarily displayable text; hexadecimal lets you represent any sequence of bytes in a readable, lossless way, so you can easily copy, store or transmit it.
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