]> Raphaƫl G. Git Repositories - youtubedl/blob - youtube_dl/aes.py
b8ff4548116403dc5166825250fedad65c20f665
[youtubedl] / youtube_dl / aes.py
1 from __future__ import unicode_literals
2
3 import base64
4 from math import ceil
5
6 from .utils import bytes_to_intlist, intlist_to_bytes
7
8 BLOCK_SIZE_BYTES = 16
9
10
11 def aes_ctr_decrypt(data, key, counter):
12 """
13 Decrypt with aes in counter mode
14
15 @param {int[]} data cipher
16 @param {int[]} key 16/24/32-Byte cipher key
17 @param {instance} counter Instance whose next_value function (@returns {int[]} 16-Byte block)
18 returns the next counter block
19 @returns {int[]} decrypted data
20 """
21 expanded_key = key_expansion(key)
22 block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES))
23
24 decrypted_data = []
25 for i in range(block_count):
26 counter_block = counter.next_value()
27 block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES]
28 block += [0] * (BLOCK_SIZE_BYTES - len(block))
29
30 cipher_counter_block = aes_encrypt(counter_block, expanded_key)
31 decrypted_data += xor(block, cipher_counter_block)
32 decrypted_data = decrypted_data[:len(data)]
33
34 return decrypted_data
35
36
37 def aes_cbc_decrypt(data, key, iv):
38 """
39 Decrypt with aes in CBC mode
40
41 @param {int[]} data cipher
42 @param {int[]} key 16/24/32-Byte cipher key
43 @param {int[]} iv 16-Byte IV
44 @returns {int[]} decrypted data
45 """
46 expanded_key = key_expansion(key)
47 block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES))
48
49 decrypted_data = []
50 previous_cipher_block = iv
51 for i in range(block_count):
52 block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES]
53 block += [0] * (BLOCK_SIZE_BYTES - len(block))
54
55 decrypted_block = aes_decrypt(block, expanded_key)
56 decrypted_data += xor(decrypted_block, previous_cipher_block)
57 previous_cipher_block = block
58 decrypted_data = decrypted_data[:len(data)]
59
60 return decrypted_data
61
62
63 def key_expansion(data):
64 """
65 Generate key schedule
66
67 @param {int[]} data 16/24/32-Byte cipher key
68 @returns {int[]} 176/208/240-Byte expanded key
69 """
70 data = data[:] # copy
71 rcon_iteration = 1
72 key_size_bytes = len(data)
73 expanded_key_size_bytes = (key_size_bytes // 4 + 7) * BLOCK_SIZE_BYTES
74
75 while len(data) < expanded_key_size_bytes:
76 temp = data[-4:]
77 temp = key_schedule_core(temp, rcon_iteration)
78 rcon_iteration += 1
79 data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes])
80
81 for _ in range(3):
82 temp = data[-4:]
83 data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes])
84
85 if key_size_bytes == 32:
86 temp = data[-4:]
87 temp = sub_bytes(temp)
88 data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes])
89
90 for _ in range(3 if key_size_bytes == 32 else 2 if key_size_bytes == 24 else 0):
91 temp = data[-4:]
92 data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes])
93 data = data[:expanded_key_size_bytes]
94
95 return data
96
97
98 def aes_encrypt(data, expanded_key):
99 """
100 Encrypt one block with aes
101
102 @param {int[]} data 16-Byte state
103 @param {int[]} expanded_key 176/208/240-Byte expanded key
104 @returns {int[]} 16-Byte cipher
105 """
106 rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1
107
108 data = xor(data, expanded_key[:BLOCK_SIZE_BYTES])
109 for i in range(1, rounds + 1):
110 data = sub_bytes(data)
111 data = shift_rows(data)
112 if i != rounds:
113 data = mix_columns(data)
114 data = xor(data, expanded_key[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES])
115
116 return data
117
118
119 def aes_decrypt(data, expanded_key):
120 """
121 Decrypt one block with aes
122
123 @param {int[]} data 16-Byte cipher
124 @param {int[]} expanded_key 176/208/240-Byte expanded key
125 @returns {int[]} 16-Byte state
126 """
127 rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1
128
129 for i in range(rounds, 0, -1):
130 data = xor(data, expanded_key[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES])
131 if i != rounds:
132 data = mix_columns_inv(data)
133 data = shift_rows_inv(data)
134 data = sub_bytes_inv(data)
135 data = xor(data, expanded_key[:BLOCK_SIZE_BYTES])
136
137 return data
138
139
140 def aes_decrypt_text(data, password, key_size_bytes):
141 """
142 Decrypt text
143 - The first 8 Bytes of decoded 'data' are the 8 high Bytes of the counter
144 - The cipher key is retrieved by encrypting the first 16 Byte of 'password'
145 with the first 'key_size_bytes' Bytes from 'password' (if necessary filled with 0's)
146 - Mode of operation is 'counter'
147
148 @param {str} data Base64 encoded string
149 @param {str,unicode} password Password (will be encoded with utf-8)
150 @param {int} key_size_bytes Possible values: 16 for 128-Bit, 24 for 192-Bit or 32 for 256-Bit
151 @returns {str} Decrypted data
152 """
153 NONCE_LENGTH_BYTES = 8
154
155 data = bytes_to_intlist(base64.b64decode(data.encode('utf-8')))
156 password = bytes_to_intlist(password.encode('utf-8'))
157
158 key = password[:key_size_bytes] + [0] * (key_size_bytes - len(password))
159 key = aes_encrypt(key[:BLOCK_SIZE_BYTES], key_expansion(key)) * (key_size_bytes // BLOCK_SIZE_BYTES)
160
161 nonce = data[:NONCE_LENGTH_BYTES]
162 cipher = data[NONCE_LENGTH_BYTES:]
163
164 class Counter(object):
165 __value = nonce + [0] * (BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES)
166
167 def next_value(self):
168 temp = self.__value
169 self.__value = inc(self.__value)
170 return temp
171
172 decrypted_data = aes_ctr_decrypt(cipher, key, Counter())
173 plaintext = intlist_to_bytes(decrypted_data)
174
175 return plaintext
176
177
178 RCON = (0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36)
179 SBOX = (0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
180 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
181 0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
182 0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
183 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
184 0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
185 0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
186 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
187 0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
188 0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
189 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
190 0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
191 0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
192 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
193 0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
194 0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16)
195 SBOX_INV = (0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
196 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
197 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
198 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
199 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
200 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
201 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
202 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
203 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
204 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
205 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
206 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
207 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
208 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
209 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
210 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d)
211 MIX_COLUMN_MATRIX = ((0x2, 0x3, 0x1, 0x1),
212 (0x1, 0x2, 0x3, 0x1),
213 (0x1, 0x1, 0x2, 0x3),
214 (0x3, 0x1, 0x1, 0x2))
215 MIX_COLUMN_MATRIX_INV = ((0xE, 0xB, 0xD, 0x9),
216 (0x9, 0xE, 0xB, 0xD),
217 (0xD, 0x9, 0xE, 0xB),
218 (0xB, 0xD, 0x9, 0xE))
219 RIJNDAEL_EXP_TABLE = (0x01, 0x03, 0x05, 0x0F, 0x11, 0x33, 0x55, 0xFF, 0x1A, 0x2E, 0x72, 0x96, 0xA1, 0xF8, 0x13, 0x35,
220 0x5F, 0xE1, 0x38, 0x48, 0xD8, 0x73, 0x95, 0xA4, 0xF7, 0x02, 0x06, 0x0A, 0x1E, 0x22, 0x66, 0xAA,
221 0xE5, 0x34, 0x5C, 0xE4, 0x37, 0x59, 0xEB, 0x26, 0x6A, 0xBE, 0xD9, 0x70, 0x90, 0xAB, 0xE6, 0x31,
222 0x53, 0xF5, 0x04, 0x0C, 0x14, 0x3C, 0x44, 0xCC, 0x4F, 0xD1, 0x68, 0xB8, 0xD3, 0x6E, 0xB2, 0xCD,
223 0x4C, 0xD4, 0x67, 0xA9, 0xE0, 0x3B, 0x4D, 0xD7, 0x62, 0xA6, 0xF1, 0x08, 0x18, 0x28, 0x78, 0x88,
224 0x83, 0x9E, 0xB9, 0xD0, 0x6B, 0xBD, 0xDC, 0x7F, 0x81, 0x98, 0xB3, 0xCE, 0x49, 0xDB, 0x76, 0x9A,
225 0xB5, 0xC4, 0x57, 0xF9, 0x10, 0x30, 0x50, 0xF0, 0x0B, 0x1D, 0x27, 0x69, 0xBB, 0xD6, 0x61, 0xA3,
226 0xFE, 0x19, 0x2B, 0x7D, 0x87, 0x92, 0xAD, 0xEC, 0x2F, 0x71, 0x93, 0xAE, 0xE9, 0x20, 0x60, 0xA0,
227 0xFB, 0x16, 0x3A, 0x4E, 0xD2, 0x6D, 0xB7, 0xC2, 0x5D, 0xE7, 0x32, 0x56, 0xFA, 0x15, 0x3F, 0x41,
228 0xC3, 0x5E, 0xE2, 0x3D, 0x47, 0xC9, 0x40, 0xC0, 0x5B, 0xED, 0x2C, 0x74, 0x9C, 0xBF, 0xDA, 0x75,
229 0x9F, 0xBA, 0xD5, 0x64, 0xAC, 0xEF, 0x2A, 0x7E, 0x82, 0x9D, 0xBC, 0xDF, 0x7A, 0x8E, 0x89, 0x80,
230 0x9B, 0xB6, 0xC1, 0x58, 0xE8, 0x23, 0x65, 0xAF, 0xEA, 0x25, 0x6F, 0xB1, 0xC8, 0x43, 0xC5, 0x54,
231 0xFC, 0x1F, 0x21, 0x63, 0xA5, 0xF4, 0x07, 0x09, 0x1B, 0x2D, 0x77, 0x99, 0xB0, 0xCB, 0x46, 0xCA,
232 0x45, 0xCF, 0x4A, 0xDE, 0x79, 0x8B, 0x86, 0x91, 0xA8, 0xE3, 0x3E, 0x42, 0xC6, 0x51, 0xF3, 0x0E,
233 0x12, 0x36, 0x5A, 0xEE, 0x29, 0x7B, 0x8D, 0x8C, 0x8F, 0x8A, 0x85, 0x94, 0xA7, 0xF2, 0x0D, 0x17,
234 0x39, 0x4B, 0xDD, 0x7C, 0x84, 0x97, 0xA2, 0xFD, 0x1C, 0x24, 0x6C, 0xB4, 0xC7, 0x52, 0xF6, 0x01)
235 RIJNDAEL_LOG_TABLE = (0x00, 0x00, 0x19, 0x01, 0x32, 0x02, 0x1a, 0xc6, 0x4b, 0xc7, 0x1b, 0x68, 0x33, 0xee, 0xdf, 0x03,
236 0x64, 0x04, 0xe0, 0x0e, 0x34, 0x8d, 0x81, 0xef, 0x4c, 0x71, 0x08, 0xc8, 0xf8, 0x69, 0x1c, 0xc1,
237 0x7d, 0xc2, 0x1d, 0xb5, 0xf9, 0xb9, 0x27, 0x6a, 0x4d, 0xe4, 0xa6, 0x72, 0x9a, 0xc9, 0x09, 0x78,
238 0x65, 0x2f, 0x8a, 0x05, 0x21, 0x0f, 0xe1, 0x24, 0x12, 0xf0, 0x82, 0x45, 0x35, 0x93, 0xda, 0x8e,
239 0x96, 0x8f, 0xdb, 0xbd, 0x36, 0xd0, 0xce, 0x94, 0x13, 0x5c, 0xd2, 0xf1, 0x40, 0x46, 0x83, 0x38,
240 0x66, 0xdd, 0xfd, 0x30, 0xbf, 0x06, 0x8b, 0x62, 0xb3, 0x25, 0xe2, 0x98, 0x22, 0x88, 0x91, 0x10,
241 0x7e, 0x6e, 0x48, 0xc3, 0xa3, 0xb6, 0x1e, 0x42, 0x3a, 0x6b, 0x28, 0x54, 0xfa, 0x85, 0x3d, 0xba,
242 0x2b, 0x79, 0x0a, 0x15, 0x9b, 0x9f, 0x5e, 0xca, 0x4e, 0xd4, 0xac, 0xe5, 0xf3, 0x73, 0xa7, 0x57,
243 0xaf, 0x58, 0xa8, 0x50, 0xf4, 0xea, 0xd6, 0x74, 0x4f, 0xae, 0xe9, 0xd5, 0xe7, 0xe6, 0xad, 0xe8,
244 0x2c, 0xd7, 0x75, 0x7a, 0xeb, 0x16, 0x0b, 0xf5, 0x59, 0xcb, 0x5f, 0xb0, 0x9c, 0xa9, 0x51, 0xa0,
245 0x7f, 0x0c, 0xf6, 0x6f, 0x17, 0xc4, 0x49, 0xec, 0xd8, 0x43, 0x1f, 0x2d, 0xa4, 0x76, 0x7b, 0xb7,
246 0xcc, 0xbb, 0x3e, 0x5a, 0xfb, 0x60, 0xb1, 0x86, 0x3b, 0x52, 0xa1, 0x6c, 0xaa, 0x55, 0x29, 0x9d,
247 0x97, 0xb2, 0x87, 0x90, 0x61, 0xbe, 0xdc, 0xfc, 0xbc, 0x95, 0xcf, 0xcd, 0x37, 0x3f, 0x5b, 0xd1,
248 0x53, 0x39, 0x84, 0x3c, 0x41, 0xa2, 0x6d, 0x47, 0x14, 0x2a, 0x9e, 0x5d, 0x56, 0xf2, 0xd3, 0xab,
249 0x44, 0x11, 0x92, 0xd9, 0x23, 0x20, 0x2e, 0x89, 0xb4, 0x7c, 0xb8, 0x26, 0x77, 0x99, 0xe3, 0xa5,
250 0x67, 0x4a, 0xed, 0xde, 0xc5, 0x31, 0xfe, 0x18, 0x0d, 0x63, 0x8c, 0x80, 0xc0, 0xf7, 0x70, 0x07)
251
252
253 def sub_bytes(data):
254 return [SBOX[x] for x in data]
255
256
257 def sub_bytes_inv(data):
258 return [SBOX_INV[x] for x in data]
259
260
261 def rotate(data):
262 return data[1:] + [data[0]]
263
264
265 def key_schedule_core(data, rcon_iteration):
266 data = rotate(data)
267 data = sub_bytes(data)
268 data[0] = data[0] ^ RCON[rcon_iteration]
269
270 return data
271
272
273 def xor(data1, data2):
274 return [x ^ y for x, y in zip(data1, data2)]
275
276
277 def rijndael_mul(a, b):
278 if(a == 0 or b == 0):
279 return 0
280 return RIJNDAEL_EXP_TABLE[(RIJNDAEL_LOG_TABLE[a] + RIJNDAEL_LOG_TABLE[b]) % 0xFF]
281
282
283 def mix_column(data, matrix):
284 data_mixed = []
285 for row in range(4):
286 mixed = 0
287 for column in range(4):
288 # xor is (+) and (-)
289 mixed ^= rijndael_mul(data[column], matrix[row][column])
290 data_mixed.append(mixed)
291 return data_mixed
292
293
294 def mix_columns(data, matrix=MIX_COLUMN_MATRIX):
295 data_mixed = []
296 for i in range(4):
297 column = data[i * 4: (i + 1) * 4]
298 data_mixed += mix_column(column, matrix)
299 return data_mixed
300
301
302 def mix_columns_inv(data):
303 return mix_columns(data, MIX_COLUMN_MATRIX_INV)
304
305
306 def shift_rows(data):
307 data_shifted = []
308 for column in range(4):
309 for row in range(4):
310 data_shifted.append(data[((column + row) & 0b11) * 4 + row])
311 return data_shifted
312
313
314 def shift_rows_inv(data):
315 data_shifted = []
316 for column in range(4):
317 for row in range(4):
318 data_shifted.append(data[((column - row) & 0b11) * 4 + row])
319 return data_shifted
320
321
322 def inc(data):
323 data = data[:] # copy
324 for i in range(len(data) - 1, -1, -1):
325 if data[i] == 255:
326 data[i] = 0
327 else:
328 data[i] = data[i] + 1
329 break
330 return data
331
332
333 __all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']