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Imported Upstream version 2014.07.11
[youtubedl] / youtube_dl / aes.py
1 __all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']
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 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)
21 block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES))
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
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
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)
70 expanded_key_size_bytes = (key_size_bytes // 4 + 7) * BLOCK_SIZE_BYTES
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 """
102 rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1
103
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])
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])
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
149 data = bytes_to_intlist(base64.b64decode(data))
150 password = bytes_to_intlist(password.encode('utf-8'))
151
152 key = password[:key_size_bytes] + [0]*(key_size_bytes - len(password))
153 key = aes_encrypt(key[:BLOCK_SIZE_BYTES], key_expansion(key)) * (key_size_bytes // BLOCK_SIZE_BYTES)
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())
166 plaintext = intlist_to_bytes(decrypted_data)
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)
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)
243
244 def sub_bytes(data):
245 return [SBOX[x] for x in data]
246
247 def sub_bytes_inv(data):
248 return [SBOX_INV[x] for x in data]
249
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):
261 return [x^y for x, y in zip(data1, data2)]
262
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):
269 data_mixed = []
270 for row in range(4):
271 mixed = 0
272 for column in range(4):
273 # xor is (+) and (-)
274 mixed ^= rijndael_mul(data[column], matrix[row][column])
275 data_mixed.append(mixed)
276 return data_mixed
277
278 def mix_columns(data, matrix=MIX_COLUMN_MATRIX):
279 data_mixed = []
280 for i in range(4):
281 column = data[i*4 : (i+1)*4]
282 data_mixed += mix_column(column, matrix)
283 return data_mixed
284
285 def mix_columns_inv(data):
286 return mix_columns(data, MIX_COLUMN_MATRIX_INV)
287
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
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
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
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