diff options
Diffstat (limited to 'yt_dlp/aes.py')
| -rw-r--r-- | yt_dlp/aes.py | 36 |
1 files changed, 12 insertions, 24 deletions
diff --git a/yt_dlp/aes.py b/yt_dlp/aes.py index b3a383c..abf54a9 100644 --- a/yt_dlp/aes.py +++ b/yt_dlp/aes.py @@ -68,7 +68,7 @@ def pad_block(block, padding_mode): raise NotImplementedError(f'Padding mode {padding_mode} is not implemented') if padding_mode == 'iso7816' and padding_size: - block = block + [0x80] # NB: += mutates list + block = [*block, 0x80] # NB: += mutates list padding_size -= 1 return block + [PADDING_BYTE[padding_mode]] * padding_size @@ -110,9 +110,7 @@ def aes_ecb_decrypt(data, key, iv=None): for i in range(block_count): block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES] encrypted_data += aes_decrypt(block, expanded_key) - encrypted_data = encrypted_data[:len(data)] - - return encrypted_data + return encrypted_data[:len(data)] def aes_ctr_decrypt(data, key, iv): @@ -148,9 +146,7 @@ def aes_ctr_encrypt(data, key, iv): cipher_counter_block = aes_encrypt(counter_block, expanded_key) encrypted_data += xor(block, cipher_counter_block) - encrypted_data = encrypted_data[:len(data)] - - return encrypted_data + return encrypted_data[:len(data)] def aes_cbc_decrypt(data, key, iv): @@ -174,9 +170,7 @@ def aes_cbc_decrypt(data, key, iv): decrypted_block = aes_decrypt(block, expanded_key) decrypted_data += xor(decrypted_block, previous_cipher_block) previous_cipher_block = block - decrypted_data = decrypted_data[:len(data)] - - return decrypted_data + return decrypted_data[:len(data)] def aes_cbc_encrypt(data, key, iv, *, padding_mode='pkcs7'): @@ -224,7 +218,7 @@ def aes_gcm_decrypt_and_verify(data, key, tag, nonce): hash_subkey = aes_encrypt([0] * BLOCK_SIZE_BYTES, key_expansion(key)) if len(nonce) == 12: - j0 = nonce + [0, 0, 0, 1] + j0 = [*nonce, 0, 0, 0, 1] else: fill = (BLOCK_SIZE_BYTES - (len(nonce) % BLOCK_SIZE_BYTES)) % BLOCK_SIZE_BYTES + 8 ghash_in = nonce + [0] * fill + bytes_to_intlist((8 * len(nonce)).to_bytes(8, 'big')) @@ -242,11 +236,11 @@ def aes_gcm_decrypt_and_verify(data, key, tag, nonce): data + [0] * (BLOCK_SIZE_BYTES - len(data) + pad_len) # pad + bytes_to_intlist((0 * 8).to_bytes(8, 'big') # length of associated data - + ((len(data) * 8).to_bytes(8, 'big'))) # length of data + + ((len(data) * 8).to_bytes(8, 'big'))), # length of data ) if tag != aes_ctr_encrypt(s_tag, key, j0): - raise ValueError("Mismatching authentication tag") + raise ValueError('Mismatching authentication tag') return decrypted_data @@ -288,9 +282,7 @@ def aes_decrypt(data, expanded_key): data = list(iter_mix_columns(data, MIX_COLUMN_MATRIX_INV)) data = shift_rows_inv(data) data = sub_bytes_inv(data) - data = xor(data, expanded_key[:BLOCK_SIZE_BYTES]) - - return data + return xor(data, expanded_key[:BLOCK_SIZE_BYTES]) def aes_decrypt_text(data, password, key_size_bytes): @@ -318,9 +310,7 @@ def aes_decrypt_text(data, password, key_size_bytes): cipher = data[NONCE_LENGTH_BYTES:] decrypted_data = aes_ctr_decrypt(cipher, key, nonce + [0] * (BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES)) - plaintext = intlist_to_bytes(decrypted_data) - - return plaintext + return intlist_to_bytes(decrypted_data) RCON = (0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36) @@ -428,9 +418,7 @@ def key_expansion(data): 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 = data[:expanded_key_size_bytes] - - return data + return data[:expanded_key_size_bytes] def iter_vector(iv): @@ -511,7 +499,7 @@ def block_product(block_x, block_y): # NIST SP 800-38D, Algorithm 1 if len(block_x) != BLOCK_SIZE_BYTES or len(block_y) != BLOCK_SIZE_BYTES: - raise ValueError("Length of blocks need to be %d bytes" % BLOCK_SIZE_BYTES) + raise ValueError(f'Length of blocks need to be {BLOCK_SIZE_BYTES} bytes') block_r = [0xE1] + [0] * (BLOCK_SIZE_BYTES - 1) block_v = block_y[:] @@ -534,7 +522,7 @@ def ghash(subkey, data): # NIST SP 800-38D, Algorithm 2 if len(data) % BLOCK_SIZE_BYTES: - raise ValueError("Length of data should be %d bytes" % BLOCK_SIZE_BYTES) + raise ValueError(f'Length of data should be {BLOCK_SIZE_BYTES} bytes') last_y = [0] * BLOCK_SIZE_BYTES for i in range(0, len(data), BLOCK_SIZE_BYTES): |