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