[cryptography] Devised a Change to RC4

Ryan Carboni ryacko at gmail.com
Wed Aug 20 04:39:47 EDT 2014


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

Table 1: 256 permuted bytes, serves as the PRGA
Table 2: 256 permuted bytes, serves as the transposition cipher
Table 3: 256 empty values, serves as the output array
Table 4: 256 empty values, serves as the output array to rescramble the
transposition cipher

i := 0 (table 1)
j := 0 (table 1)
b := 0 (table 2)
while GeneratingOutput:
    i := i + 1
    j := (j + Table 1[i]) mod 256
    swap values of Table 1[i] and Table 1[j]
    K := Table 1[(Table 1[i] + Table 1[j]) mod 256]
    output K to Table 3[Table2[i]]
    output K to Table 4[i]
    if i = 255
        while i > 0
            swap values of Table 2[i] and Table 2[Table 4[i]]
            i := i - 1
endwhile


Just wondering if it's a good change.
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