Symmetric stream cipher that XORs your text with a key-derived keystream.
RC4 is a symmetric stream cipher. A key schedule (KSA) shuffles a 256-byte state from the key, then a
generator (PRGA) produces a pseudo-random keystream that is XORed with the message bytes. Because XOR is
its own inverse, encrypting and decrypting use the exact same operation with the same key. The text is
treated as UTF-8 and the result is shown as hexadecimal or Base64.
See more information at
Wikipedia.