├── README.md ├── aes.py └── test.py /README.md: -------------------------------------------------------------------------------- 1 | A pure Python implementation of [AES](http://en.wikipedia.org/wiki/Advanced_Encryption_Standard) 2 | 3 | ### TODO 4 | 5 | * Add 192 and 256 bit versions 6 | 7 | ### License 8 | 9 | Copyright (C) 2012 Bo Zhu http://about.bozhu.me 10 | 11 | Permission is hereby granted, free of charge, to any person obtaining a 12 | copy of this software and associated documentation files (the "Software"), 13 | to deal in the Software without restriction, including without limitation 14 | the rights to use, copy, modify, merge, publish, distribute, sublicense, 15 | and/or sell copies of the Software, and to permit persons to whom the 16 | Software is furnished to do so, subject to the following conditions: 17 | 18 | The above copyright notice and this permission notice shall be included in 19 | all copies or substantial portions of the Software. 20 | 21 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 22 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 23 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 24 | THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 25 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 26 | FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 27 | DEALINGS IN THE SOFTWARE. 28 | -------------------------------------------------------------------------------- /aes.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env python 2 | 3 | 4 | """ 5 | Copyright (C) 2012 Bo Zhu http://about.bozhu.me 6 | 7 | Permission is hereby granted, free of charge, to any person obtaining a 8 | copy of this software and associated documentation files (the "Software"), 9 | to deal in the Software without restriction, including without limitation 10 | the rights to use, copy, modify, merge, publish, distribute, sublicense, 11 | and/or sell copies of the Software, and to permit persons to whom the 12 | Software is furnished to do so, subject to the following conditions: 13 | 14 | The above copyright notice and this permission notice shall be included in 15 | all copies or substantial portions of the Software. 16 | 17 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 | THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 22 | FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 23 | DEALINGS IN THE SOFTWARE. 24 | """ 25 | 26 | Sbox = ( 27 | 0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76, 28 | 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0, 29 | 0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15, 30 | 0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75, 31 | 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84, 32 | 0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF, 33 | 0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8, 34 | 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2, 35 | 0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73, 36 | 0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB, 37 | 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79, 38 | 0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08, 39 | 0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A, 40 | 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E, 41 | 0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF, 42 | 0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16, 43 | ) 44 | 45 | InvSbox = ( 46 | 0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB, 47 | 0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87, 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB, 48 | 0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E, 49 | 0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25, 50 | 0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92, 51 | 0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84, 52 | 0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06, 53 | 0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02, 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B, 54 | 0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73, 55 | 0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E, 56 | 0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89, 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B, 57 | 0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4, 58 | 0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F, 59 | 0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D, 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF, 60 | 0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61, 61 | 0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D, 62 | ) 63 | 64 | 65 | # learnt from http://cs.ucsb.edu/~koc/cs178/projects/JT/aes.c 66 | xtime = lambda a: (((a << 1) ^ 0x1B) & 0xFF) if (a & 0x80) else (a << 1) 67 | 68 | 69 | Rcon = ( 70 | 0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 71 | 0x80, 0x1B, 0x36, 0x6C, 0xD8, 0xAB, 0x4D, 0x9A, 72 | 0x2F, 0x5E, 0xBC, 0x63, 0xC6, 0x97, 0x35, 0x6A, 73 | 0xD4, 0xB3, 0x7D, 0xFA, 0xEF, 0xC5, 0x91, 0x39, 74 | ) 75 | 76 | 77 | def text2matrix(text): 78 | matrix = [] 79 | for i in range(16): 80 | byte = (text >> (8 * (15 - i))) & 0xFF 81 | if i % 4 == 0: 82 | matrix.append([byte]) 83 | else: 84 | matrix[i / 4].append(byte) 85 | return matrix 86 | 87 | 88 | def matrix2text(matrix): 89 | text = 0 90 | for i in range(4): 91 | for j in range(4): 92 | text |= (matrix[i][j] << (120 - 8 * (4 * i + j))) 93 | return text 94 | 95 | 96 | class AES: 97 | def __init__(self, master_key): 98 | self.change_key(master_key) 99 | 100 | def change_key(self, master_key): 101 | self.round_keys = text2matrix(master_key) 102 | # print self.round_keys 103 | 104 | for i in range(4, 4 * 11): 105 | self.round_keys.append([]) 106 | if i % 4 == 0: 107 | byte = self.round_keys[i - 4][0] \ 108 | ^ Sbox[self.round_keys[i - 1][1]] \ 109 | ^ Rcon[i / 4] 110 | self.round_keys[i].append(byte) 111 | 112 | for j in range(1, 4): 113 | byte = self.round_keys[i - 4][j] \ 114 | ^ Sbox[self.round_keys[i - 1][(j + 1) % 4]] 115 | self.round_keys[i].append(byte) 116 | else: 117 | for j in range(4): 118 | byte = self.round_keys[i - 4][j] \ 119 | ^ self.round_keys[i - 1][j] 120 | self.round_keys[i].append(byte) 121 | 122 | # print self.round_keys 123 | 124 | def encrypt(self, plaintext): 125 | self.plain_state = text2matrix(plaintext) 126 | 127 | self.__add_round_key(self.plain_state, self.round_keys[:4]) 128 | 129 | for i in range(1, 10): 130 | self.__round_encrypt(self.plain_state, self.round_keys[4 * i : 4 * (i + 1)]) 131 | 132 | self.__sub_bytes(self.plain_state) 133 | self.__shift_rows(self.plain_state) 134 | self.__add_round_key(self.plain_state, self.round_keys[40:]) 135 | 136 | return matrix2text(self.plain_state) 137 | 138 | def decrypt(self, ciphertext): 139 | self.cipher_state = text2matrix(ciphertext) 140 | 141 | self.__add_round_key(self.cipher_state, self.round_keys[40:]) 142 | self.__inv_shift_rows(self.cipher_state) 143 | self.__inv_sub_bytes(self.cipher_state) 144 | 145 | for i in range(9, 0, -1): 146 | self.__round_decrypt(self.cipher_state, self.round_keys[4 * i : 4 * (i + 1)]) 147 | 148 | self.__add_round_key(self.cipher_state, self.round_keys[:4]) 149 | 150 | return matrix2text(self.cipher_state) 151 | 152 | def __add_round_key(self, s, k): 153 | for i in range(4): 154 | for j in range(4): 155 | s[i][j] ^= k[i][j] 156 | 157 | 158 | def __round_encrypt(self, state_matrix, key_matrix): 159 | self.__sub_bytes(state_matrix) 160 | self.__shift_rows(state_matrix) 161 | self.__mix_columns(state_matrix) 162 | self.__add_round_key(state_matrix, key_matrix) 163 | 164 | 165 | def __round_decrypt(self, state_matrix, key_matrix): 166 | self.__add_round_key(state_matrix, key_matrix) 167 | self.__inv_mix_columns(state_matrix) 168 | self.__inv_shift_rows(state_matrix) 169 | self.__inv_sub_bytes(state_matrix) 170 | 171 | def __sub_bytes(self, s): 172 | for i in range(4): 173 | for j in range(4): 174 | s[i][j] = Sbox[s[i][j]] 175 | 176 | 177 | def __inv_sub_bytes(self, s): 178 | for i in range(4): 179 | for j in range(4): 180 | s[i][j] = InvSbox[s[i][j]] 181 | 182 | 183 | def __shift_rows(self, s): 184 | s[0][1], s[1][1], s[2][1], s[3][1] = s[1][1], s[2][1], s[3][1], s[0][1] 185 | s[0][2], s[1][2], s[2][2], s[3][2] = s[2][2], s[3][2], s[0][2], s[1][2] 186 | s[0][3], s[1][3], s[2][3], s[3][3] = s[3][3], s[0][3], s[1][3], s[2][3] 187 | 188 | 189 | def __inv_shift_rows(self, s): 190 | s[0][1], s[1][1], s[2][1], s[3][1] = s[3][1], s[0][1], s[1][1], s[2][1] 191 | s[0][2], s[1][2], s[2][2], s[3][2] = s[2][2], s[3][2], s[0][2], s[1][2] 192 | s[0][3], s[1][3], s[2][3], s[3][3] = s[1][3], s[2][3], s[3][3], s[0][3] 193 | 194 | def __mix_single_column(self, a): 195 | # please see Sec 4.1.2 in The Design of Rijndael 196 | t = a[0] ^ a[1] ^ a[2] ^ a[3] 197 | u = a[0] 198 | a[0] ^= t ^ xtime(a[0] ^ a[1]) 199 | a[1] ^= t ^ xtime(a[1] ^ a[2]) 200 | a[2] ^= t ^ xtime(a[2] ^ a[3]) 201 | a[3] ^= t ^ xtime(a[3] ^ u) 202 | 203 | 204 | def __mix_columns(self, s): 205 | for i in range(4): 206 | self.__mix_single_column(s[i]) 207 | 208 | 209 | def __inv_mix_columns(self, s): 210 | # see Sec 4.1.3 in The Design of Rijndael 211 | for i in range(4): 212 | u = xtime(xtime(s[i][0] ^ s[i][2])) 213 | v = xtime(xtime(s[i][1] ^ s[i][3])) 214 | s[i][0] ^= u 215 | s[i][1] ^= v 216 | s[i][2] ^= u 217 | s[i][3] ^= v 218 | 219 | self.__mix_columns(s) -------------------------------------------------------------------------------- /test.py: -------------------------------------------------------------------------------- 1 | __author__ = 'yousefhamza' 2 | 3 | import unittest 4 | from aes import AES 5 | 6 | class AES_TEST(unittest.TestCase): 7 | def setUp(self): 8 | master_key = 0x2b7e151628aed2a6abf7158809cf4f3c 9 | self.AES = AES(master_key) 10 | 11 | def test_encryption(self): 12 | plaintext = 0x3243f6a8885a308d313198a2e0370734 13 | encrypted = self.AES.encrypt(plaintext) 14 | 15 | self.assertEqual(encrypted, 0x3925841d02dc09fbdc118597196a0b32) 16 | 17 | def test_decryption(self): 18 | ciphertext = 0x3925841d02dc09fbdc118597196a0b32 19 | decrypted = self.AES.decrypt(ciphertext) 20 | 21 | self.assertEqual(decrypted, 0x3243f6a8885a308d313198a2e0370734) 22 | 23 | if __name__ == '__main__': 24 | unittest.main() --------------------------------------------------------------------------------