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[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))
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:
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 RCON = (0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36)
178 SBOX = (0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
179 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
180 0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
181 0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
182 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
183 0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
184 0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
185 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
186 0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
187 0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
188 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
189 0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
190 0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
191 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
192 0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
193 0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16)
194 SBOX_INV = (0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
195 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
196 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
197 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
198 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
199 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
200 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
201 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
202 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
203 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
204 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
205 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
206 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
207 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
208 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
209 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d)
210 MIX_COLUMN_MATRIX = ((0x2, 0x3, 0x1, 0x1),
211 (0x1, 0x2, 0x3, 0x1),
212 (0x1, 0x1, 0x2, 0x3),
213 (0x3, 0x1, 0x1, 0x2))
214 MIX_COLUMN_MATRIX_INV = ((0xE, 0xB, 0xD, 0x9),
215 (0x9, 0xE, 0xB, 0xD),
216 (0xD, 0x9, 0xE, 0xB),
217 (0xB, 0xD, 0x9, 0xE))
218 RIJNDAEL_EXP_TABLE = (0x01, 0x03, 0x05, 0x0F, 0x11, 0x33, 0x55, 0xFF, 0x1A, 0x2E, 0x72, 0x96, 0xA1, 0xF8, 0x13, 0x35,
219 0x5F, 0xE1, 0x38, 0x48, 0xD8, 0x73, 0x95, 0xA4, 0xF7, 0x02, 0x06, 0x0A, 0x1E, 0x22, 0x66, 0xAA,
220 0xE5, 0x34, 0x5C, 0xE4, 0x37, 0x59, 0xEB, 0x26, 0x6A, 0xBE, 0xD9, 0x70, 0x90, 0xAB, 0xE6, 0x31,
221 0x53, 0xF5, 0x04, 0x0C, 0x14, 0x3C, 0x44, 0xCC, 0x4F, 0xD1, 0x68, 0xB8, 0xD3, 0x6E, 0xB2, 0xCD,
222 0x4C, 0xD4, 0x67, 0xA9, 0xE0, 0x3B, 0x4D, 0xD7, 0x62, 0xA6, 0xF1, 0x08, 0x18, 0x28, 0x78, 0x88,
223 0x83, 0x9E, 0xB9, 0xD0, 0x6B, 0xBD, 0xDC, 0x7F, 0x81, 0x98, 0xB3, 0xCE, 0x49, 0xDB, 0x76, 0x9A,
224 0xB5, 0xC4, 0x57, 0xF9, 0x10, 0x30, 0x50, 0xF0, 0x0B, 0x1D, 0x27, 0x69, 0xBB, 0xD6, 0x61, 0xA3,
225 0xFE, 0x19, 0x2B, 0x7D, 0x87, 0x92, 0xAD, 0xEC, 0x2F, 0x71, 0x93, 0xAE, 0xE9, 0x20, 0x60, 0xA0,
226 0xFB, 0x16, 0x3A, 0x4E, 0xD2, 0x6D, 0xB7, 0xC2, 0x5D, 0xE7, 0x32, 0x56, 0xFA, 0x15, 0x3F, 0x41,
227 0xC3, 0x5E, 0xE2, 0x3D, 0x47, 0xC9, 0x40, 0xC0, 0x5B, 0xED, 0x2C, 0x74, 0x9C, 0xBF, 0xDA, 0x75,
228 0x9F, 0xBA, 0xD5, 0x64, 0xAC, 0xEF, 0x2A, 0x7E, 0x82, 0x9D, 0xBC, 0xDF, 0x7A, 0x8E, 0x89, 0x80,
229 0x9B, 0xB6, 0xC1, 0x58, 0xE8, 0x23, 0x65, 0xAF, 0xEA, 0x25, 0x6F, 0xB1, 0xC8, 0x43, 0xC5, 0x54,
230 0xFC, 0x1F, 0x21, 0x63, 0xA5, 0xF4, 0x07, 0x09, 0x1B, 0x2D, 0x77, 0x99, 0xB0, 0xCB, 0x46, 0xCA,
231 0x45, 0xCF, 0x4A, 0xDE, 0x79, 0x8B, 0x86, 0x91, 0xA8, 0xE3, 0x3E, 0x42, 0xC6, 0x51, 0xF3, 0x0E,
232 0x12, 0x36, 0x5A, 0xEE, 0x29, 0x7B, 0x8D, 0x8C, 0x8F, 0x8A, 0x85, 0x94, 0xA7, 0xF2, 0x0D, 0x17,
233 0x39, 0x4B, 0xDD, 0x7C, 0x84, 0x97, 0xA2, 0xFD, 0x1C, 0x24, 0x6C, 0xB4, 0xC7, 0x52, 0xF6, 0x01)
234 RIJNDAEL_LOG_TABLE = (0x00, 0x00, 0x19, 0x01, 0x32, 0x02, 0x1a, 0xc6, 0x4b, 0xc7, 0x1b, 0x68, 0x33, 0xee, 0xdf, 0x03,
235 0x64, 0x04, 0xe0, 0x0e, 0x34, 0x8d, 0x81, 0xef, 0x4c, 0x71, 0x08, 0xc8, 0xf8, 0x69, 0x1c, 0xc1,
236 0x7d, 0xc2, 0x1d, 0xb5, 0xf9, 0xb9, 0x27, 0x6a, 0x4d, 0xe4, 0xa6, 0x72, 0x9a, 0xc9, 0x09, 0x78,
237 0x65, 0x2f, 0x8a, 0x05, 0x21, 0x0f, 0xe1, 0x24, 0x12, 0xf0, 0x82, 0x45, 0x35, 0x93, 0xda, 0x8e,
238 0x96, 0x8f, 0xdb, 0xbd, 0x36, 0xd0, 0xce, 0x94, 0x13, 0x5c, 0xd2, 0xf1, 0x40, 0x46, 0x83, 0x38,
239 0x66, 0xdd, 0xfd, 0x30, 0xbf, 0x06, 0x8b, 0x62, 0xb3, 0x25, 0xe2, 0x98, 0x22, 0x88, 0x91, 0x10,
240 0x7e, 0x6e, 0x48, 0xc3, 0xa3, 0xb6, 0x1e, 0x42, 0x3a, 0x6b, 0x28, 0x54, 0xfa, 0x85, 0x3d, 0xba,
241 0x2b, 0x79, 0x0a, 0x15, 0x9b, 0x9f, 0x5e, 0xca, 0x4e, 0xd4, 0xac, 0xe5, 0xf3, 0x73, 0xa7, 0x57,
242 0xaf, 0x58, 0xa8, 0x50, 0xf4, 0xea, 0xd6, 0x74, 0x4f, 0xae, 0xe9, 0xd5, 0xe7, 0xe6, 0xad, 0xe8,
243 0x2c, 0xd7, 0x75, 0x7a, 0xeb, 0x16, 0x0b, 0xf5, 0x59, 0xcb, 0x5f, 0xb0, 0x9c, 0xa9, 0x51, 0xa0,
244 0x7f, 0x0c, 0xf6, 0x6f, 0x17, 0xc4, 0x49, 0xec, 0xd8, 0x43, 0x1f, 0x2d, 0xa4, 0x76, 0x7b, 0xb7,
245 0xcc, 0xbb, 0x3e, 0x5a, 0xfb, 0x60, 0xb1, 0x86, 0x3b, 0x52, 0xa1, 0x6c, 0xaa, 0x55, 0x29, 0x9d,
246 0x97, 0xb2, 0x87, 0x90, 0x61, 0xbe, 0xdc, 0xfc, 0xbc, 0x95, 0xcf, 0xcd, 0x37, 0x3f, 0x5b, 0xd1,
247 0x53, 0x39, 0x84, 0x3c, 0x41, 0xa2, 0x6d, 0x47, 0x14, 0x2a, 0x9e, 0x5d, 0x56, 0xf2, 0xd3, 0xab,
248 0x44, 0x11, 0x92, 0xd9, 0x23, 0x20, 0x2e, 0x89, 0xb4, 0x7c, 0xb8, 0x26, 0x77, 0x99, 0xe3, 0xa5,
249 0x67, 0x4a, 0xed, 0xde, 0xc5, 0x31, 0xfe, 0x18, 0x0d, 0x63, 0x8c, 0x80, 0xc0, 0xf7, 0x70, 0x07)
250
251
252 def sub_bytes(data):
253 return [SBOX[x] for x in data]
254
255
256 def sub_bytes_inv(data):
257 return [SBOX_INV[x] for x in data]
258
259
260 def rotate(data):
261 return data[1:] + [data[0]]
262
263
264 def key_schedule_core(data, rcon_iteration):
265 data = rotate(data)
266 data = sub_bytes(data)
267 data[0] = data[0] ^ RCON[rcon_iteration]
268
269 return data
270
271
272 def xor(data1, data2):
273 return [x ^ y for x, y in zip(data1, data2)]
274
275
276 def rijndael_mul(a, b):
277 if(a == 0 or b == 0):
278 return 0
279 return RIJNDAEL_EXP_TABLE[(RIJNDAEL_LOG_TABLE[a] + RIJNDAEL_LOG_TABLE[b]) % 0xFF]
280
281
282 def mix_column(data, matrix):
283 data_mixed = []
284 for row in range(4):
285 mixed = 0
286 for column in range(4):
287 # xor is (+) and (-)
288 mixed ^= rijndael_mul(data[column], matrix[row][column])
289 data_mixed.append(mixed)
290 return data_mixed
291
292
293 def mix_columns(data, matrix=MIX_COLUMN_MATRIX):
294 data_mixed = []
295 for i in range(4):
296 column = data[i * 4: (i + 1) * 4]
297 data_mixed += mix_column(column, matrix)
298 return data_mixed
299
300
301 def mix_columns_inv(data):
302 return mix_columns(data, MIX_COLUMN_MATRIX_INV)
303
304
305 def shift_rows(data):
306 data_shifted = []
307 for column in range(4):
308 for row in range(4):
309 data_shifted.append(data[((column + row) & 0b11) * 4 + row])
310 return data_shifted
311
312
313 def shift_rows_inv(data):
314 data_shifted = []
315 for column in range(4):
316 for row in range(4):
317 data_shifted.append(data[((column - row) & 0b11) * 4 + row])
318 return data_shifted
319
320
321 def inc(data):
322 data = data[:] # copy
323 for i in range(len(data) - 1, -1, -1):
324 if data[i] == 255:
325 data[i] = 0
326 else:
327 data[i] = data[i] + 1
328 break
329 return data
330
331 __all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']