X-Git-Url: https://git.rapsys.eu/youtubedl/blobdiff_plain/15b1d10671b48df598afd70e17ba21e9e64ac766..1918d37666ea9185c49ca84e64f58e4ff2a422c9:/youtube_dl/aes.py diff --git a/youtube_dl/aes.py b/youtube_dl/aes.py index 5efd0f8..c5bb3c4 100644 --- a/youtube_dl/aes.py +++ b/youtube_dl/aes.py @@ -1,7 +1,5 @@ from __future__ import unicode_literals -__all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text'] - import base64 from math import ceil @@ -62,6 +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 @@ -154,7 +180,7 @@ def aes_decrypt_text(data, password, key_size_bytes): """ NONCE_LENGTH_BYTES = 8 - data = bytes_to_intlist(base64.b64decode(data)) + data = bytes_to_intlist(base64.b64decode(data.encode('utf-8'))) password = bytes_to_intlist(password.encode('utf-8')) key = password[:key_size_bytes] + [0] * (key_size_bytes - len(password)) @@ -163,7 +189,7 @@ def aes_decrypt_text(data, password, key_size_bytes): nonce = data[:NONCE_LENGTH_BYTES] cipher = data[NONCE_LENGTH_BYTES:] - class Counter: + class Counter(object): __value = nonce + [0] * (BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES) def next_value(self): @@ -176,6 +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, @@ -329,3 +356,6 @@ def inc(data): data[i] = data[i] + 1 break return data + + +__all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']