15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)"""Abstract class for 3DES.""" 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)from compat import * #For True 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class TripleDES: 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) def __init__(self, key, mode, IV, implementation): 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if len(key) != 24: 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) raise ValueError() 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if mode != 2: 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) raise ValueError() 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if len(IV) != 8: 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) raise ValueError() 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) self.isBlockCipher = True 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) self.block_size = 8 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) self.implementation = implementation 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) self.name = "3des" 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) #CBC-Mode encryption, returns ciphertext 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) #WARNING: *MAY* modify the input as well 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) def encrypt(self, plaintext): 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) assert(len(plaintext) % 8 == 0) 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) #CBC-Mode decryption, returns plaintext 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) #WARNING: *MAY* modify the input as well 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) def decrypt(self, ciphertext): 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) assert(len(ciphertext) % 8 == 0) 27