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Commit | Line | Data |
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c8434e83 | 1 | __all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text'] |
f3bcebb1 | 2 | |
3 | import base64 | |
4 | from math import ceil | |
5 | ||
0012690a | 6 | from .utils import bytes_to_intlist, intlist_to_bytes |
48ea9cea | 7 | |
f3bcebb1 | 8 | BLOCK_SIZE_BYTES = 16 |
9 | ||
10 | def aes_ctr_decrypt(data, key, counter): | |
11 | """ | |
12 | Decrypt with aes in counter mode | |
13 | ||
14 | @param {int[]} data cipher | |
15 | @param {int[]} key 16/24/32-Byte cipher key | |
16 | @param {instance} counter Instance whose next_value function (@returns {int[]} 16-Byte block) | |
17 | returns the next counter block | |
18 | @returns {int[]} decrypted data | |
19 | """ | |
20 | expanded_key = key_expansion(key) | |
6e74bc41 | 21 | block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES)) |
f3bcebb1 | 22 | |
23 | decrypted_data=[] | |
24 | for i in range(block_count): | |
25 | counter_block = counter.next_value() | |
26 | block = data[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES] | |
27 | block += [0]*(BLOCK_SIZE_BYTES - len(block)) | |
28 | ||
29 | cipher_counter_block = aes_encrypt(counter_block, expanded_key) | |
30 | decrypted_data += xor(block, cipher_counter_block) | |
31 | decrypted_data = decrypted_data[:len(data)] | |
32 | ||
33 | return decrypted_data | |
34 | ||
c8434e83 | 35 | def aes_cbc_decrypt(data, key, iv): |
36 | """ | |
37 | Decrypt with aes in CBC mode | |
38 | ||
39 | @param {int[]} data cipher | |
40 | @param {int[]} key 16/24/32-Byte cipher key | |
41 | @param {int[]} iv 16-Byte IV | |
42 | @returns {int[]} decrypted data | |
43 | """ | |
44 | expanded_key = key_expansion(key) | |
45 | block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES)) | |
46 | ||
47 | decrypted_data=[] | |
48 | previous_cipher_block = iv | |
49 | for i in range(block_count): | |
50 | block = data[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES] | |
51 | block += [0]*(BLOCK_SIZE_BYTES - len(block)) | |
52 | ||
53 | decrypted_block = aes_decrypt(block, expanded_key) | |
54 | decrypted_data += xor(decrypted_block, previous_cipher_block) | |
55 | previous_cipher_block = block | |
56 | decrypted_data = decrypted_data[:len(data)] | |
57 | ||
58 | return decrypted_data | |
59 | ||
f3bcebb1 | 60 | def key_expansion(data): |
61 | """ | |
62 | Generate key schedule | |
63 | ||
64 | @param {int[]} data 16/24/32-Byte cipher key | |
65 | @returns {int[]} 176/208/240-Byte expanded key | |
66 | """ | |
67 | data = data[:] # copy | |
68 | rcon_iteration = 1 | |
69 | key_size_bytes = len(data) | |
48ea9cea | 70 | expanded_key_size_bytes = (key_size_bytes // 4 + 7) * BLOCK_SIZE_BYTES |
f3bcebb1 | 71 | |
72 | while len(data) < expanded_key_size_bytes: | |
73 | temp = data[-4:] | |
74 | temp = key_schedule_core(temp, rcon_iteration) | |
75 | rcon_iteration += 1 | |
76 | data += xor(temp, data[-key_size_bytes : 4-key_size_bytes]) | |
77 | ||
78 | for _ in range(3): | |
79 | temp = data[-4:] | |
80 | data += xor(temp, data[-key_size_bytes : 4-key_size_bytes]) | |
81 | ||
82 | if key_size_bytes == 32: | |
83 | temp = data[-4:] | |
84 | temp = sub_bytes(temp) | |
85 | data += xor(temp, data[-key_size_bytes : 4-key_size_bytes]) | |
86 | ||
87 | for _ in range(3 if key_size_bytes == 32 else 2 if key_size_bytes == 24 else 0): | |
88 | temp = data[-4:] | |
89 | data += xor(temp, data[-key_size_bytes : 4-key_size_bytes]) | |
90 | data = data[:expanded_key_size_bytes] | |
91 | ||
92 | return data | |
93 | ||
94 | def aes_encrypt(data, expanded_key): | |
95 | """ | |
96 | Encrypt one block with aes | |
97 | ||
98 | @param {int[]} data 16-Byte state | |
99 | @param {int[]} expanded_key 176/208/240-Byte expanded key | |
100 | @returns {int[]} 16-Byte cipher | |
101 | """ | |
48ea9cea | 102 | rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1 |
c8434e83 | 103 | |
f3bcebb1 | 104 | data = xor(data, expanded_key[:BLOCK_SIZE_BYTES]) |
105 | for i in range(1, rounds+1): | |
106 | data = sub_bytes(data) | |
107 | data = shift_rows(data) | |
108 | if i != rounds: | |
109 | data = mix_columns(data) | |
110 | data = xor(data, expanded_key[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES]) | |
c8434e83 | 111 | |
112 | return data | |
113 | ||
114 | def aes_decrypt(data, expanded_key): | |
115 | """ | |
116 | Decrypt one block with aes | |
117 | ||
118 | @param {int[]} data 16-Byte cipher | |
119 | @param {int[]} expanded_key 176/208/240-Byte expanded key | |
120 | @returns {int[]} 16-Byte state | |
121 | """ | |
122 | rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1 | |
123 | ||
124 | for i in range(rounds, 0, -1): | |
125 | data = xor(data, expanded_key[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES]) | |
126 | if i != rounds: | |
127 | data = mix_columns_inv(data) | |
128 | data = shift_rows_inv(data) | |
129 | data = sub_bytes_inv(data) | |
130 | data = xor(data, expanded_key[:BLOCK_SIZE_BYTES]) | |
f3bcebb1 | 131 | |
132 | return data | |
133 | ||
134 | def aes_decrypt_text(data, password, key_size_bytes): | |
135 | """ | |
136 | Decrypt text | |
137 | - The first 8 Bytes of decoded 'data' are the 8 high Bytes of the counter | |
138 | - The cipher key is retrieved by encrypting the first 16 Byte of 'password' | |
139 | with the first 'key_size_bytes' Bytes from 'password' (if necessary filled with 0's) | |
140 | - Mode of operation is 'counter' | |
141 | ||
142 | @param {str} data Base64 encoded string | |
143 | @param {str,unicode} password Password (will be encoded with utf-8) | |
144 | @param {int} key_size_bytes Possible values: 16 for 128-Bit, 24 for 192-Bit or 32 for 256-Bit | |
145 | @returns {str} Decrypted data | |
146 | """ | |
147 | NONCE_LENGTH_BYTES = 8 | |
148 | ||
48ea9cea PH |
149 | data = bytes_to_intlist(base64.b64decode(data)) |
150 | password = bytes_to_intlist(password.encode('utf-8')) | |
f3bcebb1 | 151 | |
152 | key = password[:key_size_bytes] + [0]*(key_size_bytes - len(password)) | |
48ea9cea | 153 | key = aes_encrypt(key[:BLOCK_SIZE_BYTES], key_expansion(key)) * (key_size_bytes // BLOCK_SIZE_BYTES) |
f3bcebb1 | 154 | |
155 | nonce = data[:NONCE_LENGTH_BYTES] | |
156 | cipher = data[NONCE_LENGTH_BYTES:] | |
157 | ||
158 | class Counter: | |
159 | __value = nonce + [0]*(BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES) | |
160 | def next_value(self): | |
161 | temp = self.__value | |
162 | self.__value = inc(self.__value) | |
163 | return temp | |
164 | ||
165 | decrypted_data = aes_ctr_decrypt(cipher, key, Counter()) | |
0012690a | 166 | plaintext = intlist_to_bytes(decrypted_data) |
f3bcebb1 | 167 | |
168 | return plaintext | |
169 | ||
170 | RCON = (0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36) | |
171 | SBOX = (0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76, | |
172 | 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0, | |
173 | 0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15, | |
174 | 0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75, | |
175 | 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84, | |
176 | 0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF, | |
177 | 0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8, | |
178 | 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2, | |
179 | 0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73, | |
180 | 0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB, | |
181 | 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79, | |
182 | 0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08, | |
183 | 0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A, | |
184 | 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E, | |
185 | 0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF, | |
186 | 0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16) | |
c8434e83 | 187 | SBOX_INV = (0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, |
188 | 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, | |
189 | 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, | |
190 | 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, | |
191 | 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, | |
192 | 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, | |
193 | 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, | |
194 | 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, | |
195 | 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, | |
196 | 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, | |
197 | 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, | |
198 | 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, | |
199 | 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, | |
200 | 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, | |
201 | 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, | |
202 | 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d) | |
203 | MIX_COLUMN_MATRIX = ((0x2,0x3,0x1,0x1), | |
204 | (0x1,0x2,0x3,0x1), | |
205 | (0x1,0x1,0x2,0x3), | |
206 | (0x3,0x1,0x1,0x2)) | |
207 | MIX_COLUMN_MATRIX_INV = ((0xE,0xB,0xD,0x9), | |
208 | (0x9,0xE,0xB,0xD), | |
209 | (0xD,0x9,0xE,0xB), | |
210 | (0xB,0xD,0x9,0xE)) | |
211 | RIJNDAEL_EXP_TABLE = (0x01, 0x03, 0x05, 0x0F, 0x11, 0x33, 0x55, 0xFF, 0x1A, 0x2E, 0x72, 0x96, 0xA1, 0xF8, 0x13, 0x35, | |
212 | 0x5F, 0xE1, 0x38, 0x48, 0xD8, 0x73, 0x95, 0xA4, 0xF7, 0x02, 0x06, 0x0A, 0x1E, 0x22, 0x66, 0xAA, | |
213 | 0xE5, 0x34, 0x5C, 0xE4, 0x37, 0x59, 0xEB, 0x26, 0x6A, 0xBE, 0xD9, 0x70, 0x90, 0xAB, 0xE6, 0x31, | |
214 | 0x53, 0xF5, 0x04, 0x0C, 0x14, 0x3C, 0x44, 0xCC, 0x4F, 0xD1, 0x68, 0xB8, 0xD3, 0x6E, 0xB2, 0xCD, | |
215 | 0x4C, 0xD4, 0x67, 0xA9, 0xE0, 0x3B, 0x4D, 0xD7, 0x62, 0xA6, 0xF1, 0x08, 0x18, 0x28, 0x78, 0x88, | |
216 | 0x83, 0x9E, 0xB9, 0xD0, 0x6B, 0xBD, 0xDC, 0x7F, 0x81, 0x98, 0xB3, 0xCE, 0x49, 0xDB, 0x76, 0x9A, | |
217 | 0xB5, 0xC4, 0x57, 0xF9, 0x10, 0x30, 0x50, 0xF0, 0x0B, 0x1D, 0x27, 0x69, 0xBB, 0xD6, 0x61, 0xA3, | |
218 | 0xFE, 0x19, 0x2B, 0x7D, 0x87, 0x92, 0xAD, 0xEC, 0x2F, 0x71, 0x93, 0xAE, 0xE9, 0x20, 0x60, 0xA0, | |
219 | 0xFB, 0x16, 0x3A, 0x4E, 0xD2, 0x6D, 0xB7, 0xC2, 0x5D, 0xE7, 0x32, 0x56, 0xFA, 0x15, 0x3F, 0x41, | |
220 | 0xC3, 0x5E, 0xE2, 0x3D, 0x47, 0xC9, 0x40, 0xC0, 0x5B, 0xED, 0x2C, 0x74, 0x9C, 0xBF, 0xDA, 0x75, | |
221 | 0x9F, 0xBA, 0xD5, 0x64, 0xAC, 0xEF, 0x2A, 0x7E, 0x82, 0x9D, 0xBC, 0xDF, 0x7A, 0x8E, 0x89, 0x80, | |
222 | 0x9B, 0xB6, 0xC1, 0x58, 0xE8, 0x23, 0x65, 0xAF, 0xEA, 0x25, 0x6F, 0xB1, 0xC8, 0x43, 0xC5, 0x54, | |
223 | 0xFC, 0x1F, 0x21, 0x63, 0xA5, 0xF4, 0x07, 0x09, 0x1B, 0x2D, 0x77, 0x99, 0xB0, 0xCB, 0x46, 0xCA, | |
224 | 0x45, 0xCF, 0x4A, 0xDE, 0x79, 0x8B, 0x86, 0x91, 0xA8, 0xE3, 0x3E, 0x42, 0xC6, 0x51, 0xF3, 0x0E, | |
225 | 0x12, 0x36, 0x5A, 0xEE, 0x29, 0x7B, 0x8D, 0x8C, 0x8F, 0x8A, 0x85, 0x94, 0xA7, 0xF2, 0x0D, 0x17, | |
226 | 0x39, 0x4B, 0xDD, 0x7C, 0x84, 0x97, 0xA2, 0xFD, 0x1C, 0x24, 0x6C, 0xB4, 0xC7, 0x52, 0xF6, 0x01) | |
227 | RIJNDAEL_LOG_TABLE = (0x00, 0x00, 0x19, 0x01, 0x32, 0x02, 0x1a, 0xc6, 0x4b, 0xc7, 0x1b, 0x68, 0x33, 0xee, 0xdf, 0x03, | |
228 | 0x64, 0x04, 0xe0, 0x0e, 0x34, 0x8d, 0x81, 0xef, 0x4c, 0x71, 0x08, 0xc8, 0xf8, 0x69, 0x1c, 0xc1, | |
229 | 0x7d, 0xc2, 0x1d, 0xb5, 0xf9, 0xb9, 0x27, 0x6a, 0x4d, 0xe4, 0xa6, 0x72, 0x9a, 0xc9, 0x09, 0x78, | |
230 | 0x65, 0x2f, 0x8a, 0x05, 0x21, 0x0f, 0xe1, 0x24, 0x12, 0xf0, 0x82, 0x45, 0x35, 0x93, 0xda, 0x8e, | |
231 | 0x96, 0x8f, 0xdb, 0xbd, 0x36, 0xd0, 0xce, 0x94, 0x13, 0x5c, 0xd2, 0xf1, 0x40, 0x46, 0x83, 0x38, | |
232 | 0x66, 0xdd, 0xfd, 0x30, 0xbf, 0x06, 0x8b, 0x62, 0xb3, 0x25, 0xe2, 0x98, 0x22, 0x88, 0x91, 0x10, | |
233 | 0x7e, 0x6e, 0x48, 0xc3, 0xa3, 0xb6, 0x1e, 0x42, 0x3a, 0x6b, 0x28, 0x54, 0xfa, 0x85, 0x3d, 0xba, | |
234 | 0x2b, 0x79, 0x0a, 0x15, 0x9b, 0x9f, 0x5e, 0xca, 0x4e, 0xd4, 0xac, 0xe5, 0xf3, 0x73, 0xa7, 0x57, | |
235 | 0xaf, 0x58, 0xa8, 0x50, 0xf4, 0xea, 0xd6, 0x74, 0x4f, 0xae, 0xe9, 0xd5, 0xe7, 0xe6, 0xad, 0xe8, | |
236 | 0x2c, 0xd7, 0x75, 0x7a, 0xeb, 0x16, 0x0b, 0xf5, 0x59, 0xcb, 0x5f, 0xb0, 0x9c, 0xa9, 0x51, 0xa0, | |
237 | 0x7f, 0x0c, 0xf6, 0x6f, 0x17, 0xc4, 0x49, 0xec, 0xd8, 0x43, 0x1f, 0x2d, 0xa4, 0x76, 0x7b, 0xb7, | |
238 | 0xcc, 0xbb, 0x3e, 0x5a, 0xfb, 0x60, 0xb1, 0x86, 0x3b, 0x52, 0xa1, 0x6c, 0xaa, 0x55, 0x29, 0x9d, | |
239 | 0x97, 0xb2, 0x87, 0x90, 0x61, 0xbe, 0xdc, 0xfc, 0xbc, 0x95, 0xcf, 0xcd, 0x37, 0x3f, 0x5b, 0xd1, | |
240 | 0x53, 0x39, 0x84, 0x3c, 0x41, 0xa2, 0x6d, 0x47, 0x14, 0x2a, 0x9e, 0x5d, 0x56, 0xf2, 0xd3, 0xab, | |
241 | 0x44, 0x11, 0x92, 0xd9, 0x23, 0x20, 0x2e, 0x89, 0xb4, 0x7c, 0xb8, 0x26, 0x77, 0x99, 0xe3, 0xa5, | |
242 | 0x67, 0x4a, 0xed, 0xde, 0xc5, 0x31, 0xfe, 0x18, 0x0d, 0x63, 0x8c, 0x80, 0xc0, 0xf7, 0x70, 0x07) | |
f3bcebb1 | 243 | |
244 | def sub_bytes(data): | |
48ea9cea | 245 | return [SBOX[x] for x in data] |
f3bcebb1 | 246 | |
c8434e83 | 247 | def sub_bytes_inv(data): |
248 | return [SBOX_INV[x] for x in data] | |
249 | ||
f3bcebb1 | 250 | def rotate(data): |
251 | return data[1:] + [data[0]] | |
252 | ||
253 | def key_schedule_core(data, rcon_iteration): | |
254 | data = rotate(data) | |
255 | data = sub_bytes(data) | |
256 | data[0] = data[0] ^ RCON[rcon_iteration] | |
257 | ||
258 | return data | |
259 | ||
260 | def xor(data1, data2): | |
48ea9cea | 261 | return [x^y for x, y in zip(data1, data2)] |
f3bcebb1 | 262 | |
c8434e83 | 263 | def rijndael_mul(a, b): |
264 | if(a==0 or b==0): | |
265 | return 0 | |
266 | return RIJNDAEL_EXP_TABLE[(RIJNDAEL_LOG_TABLE[a] + RIJNDAEL_LOG_TABLE[b]) % 0xFF] | |
267 | ||
268 | def mix_column(data, matrix): | |
f3bcebb1 | 269 | data_mixed = [] |
270 | for row in range(4): | |
271 | mixed = 0 | |
272 | for column in range(4): | |
c8434e83 | 273 | # xor is (+) and (-) |
274 | mixed ^= rijndael_mul(data[column], matrix[row][column]) | |
f3bcebb1 | 275 | data_mixed.append(mixed) |
276 | return data_mixed | |
277 | ||
c8434e83 | 278 | def mix_columns(data, matrix=MIX_COLUMN_MATRIX): |
f3bcebb1 | 279 | data_mixed = [] |
280 | for i in range(4): | |
281 | column = data[i*4 : (i+1)*4] | |
c8434e83 | 282 | data_mixed += mix_column(column, matrix) |
f3bcebb1 | 283 | return data_mixed |
284 | ||
c8434e83 | 285 | def mix_columns_inv(data): |
286 | return mix_columns(data, MIX_COLUMN_MATRIX_INV) | |
287 | ||
f3bcebb1 | 288 | def shift_rows(data): |
289 | data_shifted = [] | |
290 | for column in range(4): | |
291 | for row in range(4): | |
292 | data_shifted.append( data[((column + row) & 0b11) * 4 + row] ) | |
293 | return data_shifted | |
294 | ||
c8434e83 | 295 | def shift_rows_inv(data): |
296 | data_shifted = [] | |
297 | for column in range(4): | |
298 | for row in range(4): | |
299 | data_shifted.append( data[((column - row) & 0b11) * 4 + row] ) | |
300 | return data_shifted | |
301 | ||
f3bcebb1 | 302 | def inc(data): |
303 | data = data[:] # copy | |
304 | for i in range(len(data)-1,-1,-1): | |
305 | if data[i] == 255: | |
306 | data[i] = 0 | |
307 | else: | |
308 | data[i] = data[i] + 1 | |
309 | break | |
310 | return data |