303 lines
7.6 KiB
Python
303 lines
7.6 KiB
Python
# Huge thanks to Cairnarvon
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# https://gist.github.com/Cairnarvon/5075687
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# Initial permutation
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IP = (
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58, 50, 42, 34, 26, 18, 10, 2,
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60, 52, 44, 36, 28, 20, 12, 4,
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62, 54, 46, 38, 30, 22, 14, 6,
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64, 56, 48, 40, 32, 24, 16, 8,
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57, 49, 41, 33, 25, 17, 9, 1,
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59, 51, 43, 35, 27, 19, 11, 3,
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61, 53, 45, 37, 29, 21, 13, 5,
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63, 55, 47, 39, 31, 23, 15, 7,
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)
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# Final permutation, FP = IP^(-1)
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FP = (
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40, 8, 48, 16, 56, 24, 64, 32,
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39, 7, 47, 15, 55, 23, 63, 31,
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38, 6, 46, 14, 54, 22, 62, 30,
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37, 5, 45, 13, 53, 21, 61, 29,
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36, 4, 44, 12, 52, 20, 60, 28,
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35, 3, 43, 11, 51, 19, 59, 27,
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34, 2, 42, 10, 50, 18, 58, 26,
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33, 1, 41, 9, 49, 17, 57, 25,
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)
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# Permuted-choice 1 from the key bits to yield C and D.
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# Note that bits 8,16... are left out: They are intended for a parity check.
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PC1_C = (
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57, 49, 41, 33, 25, 17, 9,
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1, 58, 50, 42, 34, 26, 18,
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10, 2, 59, 51, 43, 35, 27,
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19, 11, 3, 60, 52, 44, 36,
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)
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PC1_D = (
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63, 55, 47, 39, 31, 23, 15,
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7, 62, 54, 46, 38, 30, 22,
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14, 6, 61, 53, 45, 37, 29,
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21, 13, 5, 28, 20, 12, 4,
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)
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# Permuted-choice 2, to pick out the bits from the CD array that generate the
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# key schedule.
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PC2_C = (
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14, 17, 11, 24, 1, 5,
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3, 28, 15, 6, 21, 10,
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23, 19, 12, 4, 26, 8,
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16, 7, 27, 20, 13, 2,
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)
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PC2_D = (
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41, 52, 31, 37, 47, 55,
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30, 40, 51, 45, 33, 48,
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44, 49, 39, 56, 34, 53,
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46, 42, 50, 36, 29, 32,
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)
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# The C and D arrays are used to calculate the key schedule.
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C = [0] * 28
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D = [0] * 28
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# The key schedule. Generated from the key.
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KS = [[0] * 48 for _ in range(16)]
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# The E bit-selection table.
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E = [0] * 48
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e2 = (
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32, 1, 2, 3, 4, 5,
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4, 5, 6, 7, 8, 9,
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8, 9, 10, 11, 12, 13,
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12, 13, 14, 15, 16, 17,
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16, 17, 18, 19, 20, 21,
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20, 21, 22, 23, 24, 25,
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24, 25, 26, 27, 28, 29,
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28, 29, 30, 31, 32, 1,
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)
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# S-boxes.
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S = (
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(
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14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
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0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
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4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
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15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13
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),
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(
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15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
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3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
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0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
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13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9
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),
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(
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10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
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13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
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13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
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1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12
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),
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(
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7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
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13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
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10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
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3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14
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),
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(
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2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
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14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
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4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
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11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3
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),
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(
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12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
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10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
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9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
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4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13
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),
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(
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4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
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13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
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1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
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6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12
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),
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(
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13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
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1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
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7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
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2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11
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)
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)
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# P is a permutation on the selected combination of the current L and key.
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P = (
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16, 7, 20, 21,
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29, 12, 28, 17,
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1, 15, 23, 26,
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5, 18, 31, 10,
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2, 8, 24, 14,
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32, 27, 3, 9,
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19, 13, 30, 6,
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22, 11, 4, 25,
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)
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# The combination of the key and the input, before selection.
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preS = [0] * 48
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def __setkey(key):
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"""
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Set up the key schedule from the encryption key.
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"""
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global C, D, KS, E
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shifts = (1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1)
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# First, generate C and D by permuting the key. The lower order bit of each
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# 8-bit char is not used, so C and D are only 28 bits apiece.
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for i in range(28):
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C[i] = key[PC1_C[i] - 1]
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D[i] = key[PC1_D[i] - 1]
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for i in range(16):
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# rotate
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for k in range(shifts[i]):
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temp = C[0]
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for j in range(27):
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C[j] = C[j + 1]
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C[27] = temp
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temp = D[0]
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for j in range(27):
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D[j] = D[j + 1]
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D[27] = temp
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# get Ki. Note C and D are concatenated
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for j in range(24):
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KS[i][j] = C[PC2_C[j] - 1]
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KS[i][j + 24] = D[PC2_D[j] - 28 - 1]
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# load E with the initial E bit selections
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for i in range(48):
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E[i] = e2[i]
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def __encrypt(block):
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global preS
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left, right = [], [] # block in two halves
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f = [0] * 32
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# First, permute the bits in the input
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for j in range(32):
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left.append(block[IP[j] - 1])
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for j in range(32, 64):
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right.append(block[IP[j] - 1])
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# Perform an encryption operation 16 times.
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for i in range(16):
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# Save the right array, which will be the new left.
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old = right[:]
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# Expand right to 48 bits using the E selector and exclusive-or with
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# the current key bits.
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for j in range(48):
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preS[j] = right[E[j] - 1] ^ KS[i][j]
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# The pre-select bits are now considered in 8 groups of 6 bits each.
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# The 8 selection functions map these 6-bit quantities into 4-bit
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# quantities and the results are permuted to make an f(R, K).
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# The indexing into the selection functions is peculiar; it could be
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# simplified by rewriting the tables.
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for j in range(8):
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temp = 6 * j
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k = S[j][(preS[temp + 0] << 5) +
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(preS[temp + 1] << 3) +
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(preS[temp + 2] << 2) +
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(preS[temp + 3] << 1) +
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(preS[temp + 4] << 0) +
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(preS[temp + 5] << 4)]
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temp = 4 * j
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f[temp + 0] = (k >> 3) & 1
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f[temp + 1] = (k >> 2) & 1
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f[temp + 2] = (k >> 1) & 1
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f[temp + 3] = (k >> 0) & 1
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# The new right is left ^ f(R, K).
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# The f here has to be permuted first, though.
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for j in range(32):
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right[j] = left[j] ^ f[P[j] - 1]
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# Finally the new left (the original right) is copied back.
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left = old
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# The output left and right are reversed.
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left, right = right, left
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# The final output gets the inverse permutation of the very original
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for j in range(64):
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i = FP[j]
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if i < 33:
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block[j] = left[i - 1]
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else:
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block[j] = right[i - 33]
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return block
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def crypt(pw, salt):
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iobuf = []
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# break pw into 64 bits
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block = []
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for c in pw:
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c = ord(c)
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for j in range(7):
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block.append((c >> (6 - j)) & 1)
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block.append(0)
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block += [0] * (64 - len(block))
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# set key based on pw
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__setkey(block)
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for i in range(2):
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# store salt at beginning of results
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iobuf.append(salt[i])
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c = ord(salt[i])
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if c > ord('Z'):
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c -= 6
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if c > ord('9'):
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c -= 7
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c -= ord('.')
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# use salt to effect the E-bit selection
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for j in range(6):
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if (c >> j) & 1:
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E[6 * i + j], E[6 * i + j + 24] = E[6 * i + j + 24], E[6 * i + j]
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# call DES encryption 25 times using pw as key and initial data = 0
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block = [0] * 66
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for i in range(25):
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block = __encrypt(block)
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# format encrypted block for standard crypt(3) output
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for i in range(11):
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c = 0
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for j in range(6):
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c <<= 1
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c |= block[6 * i + j]
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c += ord('.')
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if c > ord('9'):
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c += 7
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if c > ord('Z'):
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c += 6
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iobuf.append(chr(c))
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return ''.join(iobuf)
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