X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=youtube_dl%2Faes.py;h=461bb6d413a91bde8f408667d838088c5f8e11be;hb=86b7c00adca578b36138b165b0add5978972917e;hp=2db8ab3a182a2868bd60456bf140a20e19fb0756;hpb=8bcc875676b56c062a4fdd81763a6adb0fb1390c;p=youtube-dl diff --git a/youtube_dl/aes.py b/youtube_dl/aes.py index 2db8ab3a1..461bb6d41 100644 --- a/youtube_dl/aes.py +++ b/youtube_dl/aes.py @@ -1,8 +1,8 @@ -__all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text'] +from __future__ import unicode_literals -import base64 from math import ceil +from .compat import compat_b64decode from .utils import bytes_to_intlist, intlist_to_bytes BLOCK_SIZE_BYTES = 16 @@ -24,8 +24,8 @@ def aes_ctr_decrypt(data, key, counter): decrypted_data = [] for i in range(block_count): counter_block = counter.next_value() - block = data[i *BLOCK_SIZE_BYTES: (i +1) *BLOCK_SIZE_BYTES] - block += [0] *(BLOCK_SIZE_BYTES - len(block)) + block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES] + block += [0] * (BLOCK_SIZE_BYTES - len(block)) cipher_counter_block = aes_encrypt(counter_block, expanded_key) decrypted_data += xor(block, cipher_counter_block) @@ -49,8 +49,8 @@ def aes_cbc_decrypt(data, key, iv): decrypted_data = [] previous_cipher_block = iv for i in range(block_count): - block = data[i *BLOCK_SIZE_BYTES: (i +1) *BLOCK_SIZE_BYTES] - block += [0] *(BLOCK_SIZE_BYTES - len(block)) + block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES] + block += [0] * (BLOCK_SIZE_BYTES - len(block)) decrypted_block = aes_decrypt(block, expanded_key) decrypted_data += xor(decrypted_block, previous_cipher_block) @@ -60,6 +60,34 @@ def aes_cbc_decrypt(data, key, iv): return decrypted_data +def aes_cbc_encrypt(data, key, iv): + """ + Encrypt with aes in CBC mode. Using PKCS#7 padding + + @param {int[]} data cleartext + @param {int[]} key 16/24/32-Byte cipher key + @param {int[]} iv 16-Byte IV + @returns {int[]} encrypted data + """ + expanded_key = key_expansion(key) + block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES)) + + encrypted_data = [] + previous_cipher_block = iv + for i in range(block_count): + block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES] + remaining_length = BLOCK_SIZE_BYTES - len(block) + block += [remaining_length] * remaining_length + mixed_block = xor(block, previous_cipher_block) + + encrypted_block = aes_encrypt(mixed_block, expanded_key) + encrypted_data += encrypted_block + + previous_cipher_block = encrypted_block + + return encrypted_data + + def key_expansion(data): """ Generate key schedule @@ -76,20 +104,20 @@ def key_expansion(data): temp = data[-4:] temp = key_schedule_core(temp, rcon_iteration) rcon_iteration += 1 - data += xor(temp, data[-key_size_bytes: 4 -key_size_bytes]) + data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes]) for _ in range(3): temp = data[-4:] - data += xor(temp, data[-key_size_bytes: 4 -key_size_bytes]) + data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes]) if key_size_bytes == 32: temp = data[-4:] temp = sub_bytes(temp) - data += xor(temp, data[-key_size_bytes: 4 -key_size_bytes]) + data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes]) - for _ in range(3 if key_size_bytes == 32 else 2 if key_size_bytes == 24 else 0): + for _ in range(3 if key_size_bytes == 32 else 2 if key_size_bytes == 24 else 0): temp = data[-4:] - data += xor(temp, data[-key_size_bytes: 4 -key_size_bytes]) + data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes]) data = data[:expanded_key_size_bytes] return data @@ -106,12 +134,12 @@ def aes_encrypt(data, expanded_key): rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1 data = xor(data, expanded_key[:BLOCK_SIZE_BYTES]) - for i in range(1, rounds +1): + for i in range(1, rounds + 1): data = sub_bytes(data) data = shift_rows(data) if i != rounds: data = mix_columns(data) - data = xor(data, expanded_key[i *BLOCK_SIZE_BYTES: (i +1) *BLOCK_SIZE_BYTES]) + data = xor(data, expanded_key[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES]) return data @@ -127,7 +155,7 @@ def aes_decrypt(data, expanded_key): rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1 for i in range(rounds, 0, -1): - data = xor(data, expanded_key[i *BLOCK_SIZE_BYTES: (i +1) *BLOCK_SIZE_BYTES]) + data = xor(data, expanded_key[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES]) if i != rounds: data = mix_columns_inv(data) data = shift_rows_inv(data) @@ -152,17 +180,17 @@ def aes_decrypt_text(data, password, key_size_bytes): """ NONCE_LENGTH_BYTES = 8 - data = bytes_to_intlist(base64.b64decode(data)) + data = bytes_to_intlist(compat_b64decode(data)) password = bytes_to_intlist(password.encode('utf-8')) - key = password[:key_size_bytes] + [0] *(key_size_bytes - len(password)) + key = password[:key_size_bytes] + [0] * (key_size_bytes - len(password)) key = aes_encrypt(key[:BLOCK_SIZE_BYTES], key_expansion(key)) * (key_size_bytes // BLOCK_SIZE_BYTES) nonce = data[:NONCE_LENGTH_BYTES] cipher = data[NONCE_LENGTH_BYTES:] - class Counter: - __value = nonce + [0] *(BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES) + class Counter(object): + __value = nonce + [0] * (BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES) def next_value(self): temp = self.__value @@ -174,6 +202,7 @@ def aes_decrypt_text(data, password, key_size_bytes): return plaintext + RCON = (0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36) SBOX = (0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76, 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0, @@ -270,7 +299,7 @@ def key_schedule_core(data, rcon_iteration): def xor(data1, data2): - return [x^y for x, y in zip(data1, data2)] + return [x ^ y for x, y in zip(data1, data2)] def rijndael_mul(a, b): @@ -293,7 +322,7 @@ def mix_column(data, matrix): def mix_columns(data, matrix=MIX_COLUMN_MATRIX): data_mixed = [] for i in range(4): - column = data[i *4: (i +1) *4] + column = data[i * 4: (i + 1) * 4] data_mixed += mix_column(column, matrix) return data_mixed @@ -320,10 +349,13 @@ def shift_rows_inv(data): def inc(data): data = data[:] # copy - for i in range(len(data) -1, -1, -1): + for i in range(len(data) - 1, -1, -1): if data[i] == 255: data[i] = 0 else: data[i] = data[i] + 1 break return data + + +__all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']