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221 lines
9.4 KiB
Python
221 lines
9.4 KiB
Python
#!/usr/bin/env python
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# vim:ts=4:sw=4:softtabstop=4:smarttab:expandtab
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import sys
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ECB = 0
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CBC = 1
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class Des(object):
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__pc1 = [56, 48, 40, 32, 24, 16, 8, 0, 57, 49, 41, 33, 25, 17,
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9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35,
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62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21,
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13, 5, 60, 52, 44, 36, 28, 20, 12, 4, 27, 19, 11, 3]
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__left_rotations = [1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1]
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__pc2 = [13, 16, 10, 23, 0, 4,2, 27, 14, 5, 20, 9,
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22, 18, 11, 3, 25, 7, 15, 6, 26, 19, 12, 1,
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40, 51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47,
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43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31]
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__ip = [57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3,
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61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7,
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56, 48, 40, 32, 24, 16, 8, 0, 58, 50, 42, 34, 26, 18, 10, 2,
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60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6]
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__expansion_table = [31, 0, 1, 2, 3, 4, 3, 4, 5, 6, 7, 8,
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7, 8, 9, 10, 11, 12,11, 12, 13, 14, 15, 16,
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15, 16, 17, 18, 19, 20,19, 20, 21, 22, 23, 24,
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23, 24, 25, 26, 27, 28,27, 28, 29, 30, 31, 0]
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__sbox = [[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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[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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[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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[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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[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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[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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[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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[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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__p = [15, 6, 19, 20, 28, 11,27, 16, 0, 14, 22, 25,
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4, 17, 30, 9, 1, 7,23,13, 31, 26, 2, 8,18, 12, 29, 5, 21, 10,3, 24]
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__fp = [39, 7, 47, 15, 55, 23, 63, 31,38, 6, 46, 14, 54, 22, 62, 30,
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37, 5, 45, 13, 53, 21, 61, 29,36, 4, 44, 12, 52, 20, 60, 28,
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35, 3, 43, 11, 51, 19, 59, 27,34, 2, 42, 10, 50, 18, 58, 26,
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33, 1, 41, 9, 49, 17, 57, 25,32, 0, 40, 8, 48, 16, 56, 24]
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# Type of crypting being done
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ENCRYPT = 0x00
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DECRYPT = 0x01
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def __init__(self, key, mode=ECB, IV=None):
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if len(key) != 8:
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raise ValueError("Invalid DES key size. Key must be exactly 8 bytes long.")
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self.block_size = 8
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self.key_size = 8
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self.__padding = ''
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self.setMode(mode)
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if IV:
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self.setIV(IV)
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self.L = []
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self.R = []
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self.Kn = [ [0] * 48 ] * 16 # 16 48-bit keys (K1 - K16)
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self.final = []
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self.setKey(key)
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def getKey(self):
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return self.__key
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def setKey(self, key):
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self.__key = key
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self.__create_sub_keys()
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def getMode(self):
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return self.__mode
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def setMode(self, mode):
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self.__mode = mode
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def getIV(self):
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return self.__iv
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def setIV(self, IV):
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if not IV or len(IV) != self.block_size:
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raise ValueError("Invalid Initial Value (IV), must be a multiple of " + str(self.block_size) + " bytes")
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self.__iv = IV
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def getPadding(self):
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return self.__padding
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def __String_to_BitList(self, data):
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l = len(data) * 8
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result = [0] * l
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pos = 0
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for c in data:
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i = 7
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ch = ord(c)
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while i >= 0:
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if ch & (1 << i) != 0:
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result[pos] = 1
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else:
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result[pos] = 0
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pos += 1
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i -= 1
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return result
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def __BitList_to_String(self, data):
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result = ''
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pos = 0
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c = 0
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while pos < len(data):
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c += data[pos] << (7 - (pos % 8))
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if (pos % 8) == 7:
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result += chr(c)
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c = 0
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pos += 1
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return result
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def __permutate(self, table, block):
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return [block[x] for x in table]
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def __create_sub_keys(self):
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key = self.__permutate(Des.__pc1, self.__String_to_BitList(self.getKey()))
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i = 0
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self.L = key[:28]
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self.R = key[28:]
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while i < 16:
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j = 0
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while j < Des.__left_rotations[i]:
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self.L.append(self.L[0])
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del self.L[0]
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self.R.append(self.R[0])
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del self.R[0]
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j += 1
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self.Kn[i] = self.__permutate(Des.__pc2, self.L + self.R)
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i += 1
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def __des_crypt(self, block, crypt_type):
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block = self.__permutate(Des.__ip, block)
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self.L = block[:32]
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self.R = block[32:]
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if crypt_type == Des.ENCRYPT:
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iteration = 0
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iteration_adjustment = 1
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else:
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iteration = 15
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iteration_adjustment = -1
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i = 0
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while i < 16:
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tempR = self.R[:]
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self.R = self.__permutate(Des.__expansion_table, self.R)
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self.R = [x ^ y for x,y in zip(self.R, self.Kn[iteration])]
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B = [self.R[:6], self.R[6:12], self.R[12:18], self.R[18:24], self.R[24:30], self.R[30:36], self.R[36:42], self.R[42:]]
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j = 0
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Bn = [0] * 32
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pos = 0
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while j < 8:
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m = (B[j][0] << 1) + B[j][5]
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n = (B[j][1] << 3) + (B[j][2] << 2) + (B[j][3] << 1) + B[j][4]
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v = Des.__sbox[j][(m << 4) + n]
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Bn[pos] = (v & 8) >> 3
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Bn[pos + 1] = (v & 4) >> 2
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Bn[pos + 2] = (v & 2) >> 1
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Bn[pos + 3] = v & 1
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pos += 4
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j += 1
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self.R = self.__permutate(Des.__p, Bn)
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self.R = [x ^ y for x, y in zip(self.R, self.L)]
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self.L = tempR
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i += 1
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iteration += iteration_adjustment
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self.final = self.__permutate(Des.__fp, self.R + self.L)
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return self.final
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def crypt(self, data, crypt_type):
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if not data:
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return ''
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if len(data) % self.block_size != 0:
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if crypt_type == Des.DECRYPT: # Decryption must work on 8 byte blocks
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raise ValueError("Invalid data length, data must be a multiple of " + str(self.block_size) + " bytes\n.")
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if not self.getPadding():
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raise ValueError("Invalid data length, data must be a multiple of " + str(self.block_size) + " bytes\n. Try setting the optional padding character")
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else:
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data += (self.block_size - (len(data) % self.block_size)) * self.getPadding()
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if self.getMode() == CBC:
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if self.getIV():
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iv = self.__String_to_BitList(self.getIV())
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else:
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raise ValueError("For CBC mode, you must supply the Initial Value (IV) for ciphering")
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i = 0
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dict = {}
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result = []
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while i < len(data):
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block = self.__String_to_BitList(data[i:i+8])
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if self.getMode() == CBC:
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if crypt_type == Des.ENCRYPT:
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block = [x ^ y for x, y in zip(block, iv)]
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processed_block = self.__des_crypt(block, crypt_type)
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if crypt_type == Des.DECRYPT:
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processed_block = [x ^ y for x, y in zip(processed_block, iv)]
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iv = block
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else:
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iv = processed_block
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else:
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processed_block = self.__des_crypt(block, crypt_type)
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result.append(self.__BitList_to_String(processed_block))
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i += 8
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if crypt_type == Des.DECRYPT and self.getPadding():
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s = result[-1]
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while s[-1] == self.getPadding():
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s = s[:-1]
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result[-1] = s
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return ''.join(result)
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def encrypt(self, data, pad=''):
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self.__padding = pad
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return self.crypt(data, Des.ENCRYPT)
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def decrypt(self, data, pad=''):
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self.__padding = pad
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return self.crypt(data, Des.DECRYPT)
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