[Cryptography] Made a modification to RC4

[Ryan Carboni]

Feed RC4 through a transposition cipher... essentially a single round
2048-bit block cipher.

S1: 256 permuted bytes, serves as the PRGA
S2: 256 permuted bytes, serves as the transposition cipher
S3: 256 empty values, serves as the output array
S4: 256 empty values, serves as the output array to rescramble the
transposition cipher

i := 0 (S1)
j := 0 (S1)
while GeneratingOutput:
    i := i + 1
    j := (j + S1[i]) mod 256
    swap values of S1[i] and S1[j]
    K := S1[(S1[i] + S1[j]) mod 256]
    output K to position S2[i] in S3
    XOR K and S4[i]
    if i = 255
        output S3
        while i > 0
            swap values of S2[i] and S2[S4[i]]
            i := i - 1
endwhile


This should flatten the biases in the first 256 bytes of RC4. It should
also reduce the relationship between byte values and the internal state.

I call this XARC4.
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