In cryptography, RC4 (Rivest Cipher 4) is a stream cipher. It is also also known as ARC4 or ARCFOUR meaning Alleged RC4. RC4 generates a pseudorandom stream of bits (a keystream). The cipher makes use of a secret internal state which consists of two parts: one is permutation of all 256 possible bytes, Anthoer is Two 8-bit index-pointers (denoted "i" and "j").