Crypt::Stream::RC4 - Stream cipher RC4
   use Crypt::Stream::RC4;
   # encrypt
   $key = "1234567890123456";
   $stream = Crypt::Stream::RC4->new($key);
   $ct = $stream->crypt("plain message");
   # decrypt
   $key = "1234567890123456";
   $stream = Crypt::Stream::RC4->new($key);
   $pt = $stream->crypt($ct);
Provides an interface to the RC4 stream cipher.
 $stream = Crypt::Stream::RC4->new($key);
 # $key .. length 5-256 bytes (40 - 2048 bits)
 $ciphertext = $stream->crypt($plaintext);
 #or
 $plaintext = $stream->crypt($ciphertext);
 $random_key = $stream->keystream($length);
  - Crypt::Stream::ChaCha, Crypt::Stream::Sober128, Crypt::Stream::Salsa20,
      Crypt::Stream::Sosemanuk
 
  - <https://en.wikipedia.org/wiki/RC4_cipher>