1a02191e04bc25c4935f804f2c080ae28663d096dBen Murdoch# Author: Trevor Perrin 2a02191e04bc25c4935f804f2c080ae28663d096dBen Murdoch# See the LICENSE file for legal information regarding use of this file. 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 4a02191e04bc25c4935f804f2c080ae28663d096dBen Murdoch"""Abstract class for 3DES.""" 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 6a02191e04bc25c4935f804f2c080ae28663d096dBen Murdochclass TripleDES(object): 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) def __init__(self, key, mode, IV, implementation): 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if len(key) != 24: 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) raise ValueError() 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if mode != 2: 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) raise ValueError() 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if len(IV) != 8: 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) raise ValueError() 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) self.isBlockCipher = True 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) self.block_size = 8 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) self.implementation = implementation 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) self.name = "3des" 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) #CBC-Mode encryption, returns ciphertext 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) #WARNING: *MAY* modify the input as well 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) def encrypt(self, plaintext): 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) assert(len(plaintext) % 8 == 0) 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) #CBC-Mode decryption, returns plaintext 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) #WARNING: *MAY* modify the input as well 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) def decrypt(self, ciphertext): 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) assert(len(ciphertext) % 8 == 0) 28