The ARCFour keystream is implemented in the
class ARCFour, which defines the following additional constant:
A property name in the attributes map used to initialize instances of
ARCFour. The value mapped must be a byte array of the secret key, which can be up to 256 bytes long.
Also note that using the ARCFour PRNG as a stream cipher is as simple as:
IRandom arcfour; // initialized elsewhere.
byte in, out;
out = in ^ arcfour.next();