Annotate with bug number.

[youtubedl] / youtube_dl / aes.py

diff --git a/youtube_dl/aes.py b/youtube_dl/aes.py
index 7817adcfdd546f70cfb76e0634b8df8ddbcaf8e0..c5bb3c4ef1561847a1025a0b35095a2224582efe 100644 (file)
--- a/youtube_dl/aes.py
+++ b/youtube_dl/aes.py
@@ -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
@@ -161,7 +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):
@@ -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,
@@ -328,4 +357,5 @@ def inc(data):
             break
     return data
 
+
 __all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']