From afcddfd7c155cd88e73075c7faf2aaa39b065e99 Mon Sep 17 00:00:00 2001 From: Lonami Exo Date: Thu, 17 Aug 2017 18:12:19 +0200 Subject: [PATCH] Remove seemingly useless array copies on aes.py (#199) --- telethon/crypto/aes.py | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/telethon/crypto/aes.py b/telethon/crypto/aes.py index c455c2b6..9a4459df 100644 --- a/telethon/crypto/aes.py +++ b/telethon/crypto/aes.py @@ -5,7 +5,9 @@ import pyaes class AES: @staticmethod def decrypt_ige(cipher_text, key, iv): - """Decrypts the given text in 16-bytes blocks by using the given key and 32-bytes initialization vector""" + """Decrypts the given text in 16-bytes blocks by using the + given key and 32-bytes initialization vector + """ iv1 = iv[:len(iv) // 2] iv2 = iv[len(iv) // 2:] @@ -17,8 +19,8 @@ class AES: cipher_text_block = [0] * 16 for block_index in range(blocks_count): for i in range(16): - cipher_text_block[i] = cipher_text[block_index * 16 + i] ^ iv2[ - i] + cipher_text_block[i] = \ + cipher_text[block_index * 16 + i] ^ iv2[i] plain_text_block = aes.decrypt(cipher_text_block) @@ -26,17 +28,19 @@ class AES: plain_text_block[i] ^= iv1[i] iv1 = cipher_text[block_index * 16:block_index * 16 + 16] - iv2 = plain_text_block[:] + iv2 = plain_text_block - plain_text.extend(plain_text_block[:]) + plain_text.extend(plain_text_block) return bytes(plain_text) @staticmethod def encrypt_ige(plain_text, key, iv): - """Encrypts the given text in 16-bytes blocks by using the given key and 32-bytes initialization vector""" + """Encrypts the given text in 16-bytes blocks by using the + given key and 32-bytes initialization vector + """ - # Add random padding if and only if it's not evenly divisible by 16 already + # Add random padding iff it's not evenly divisible by 16 already if len(plain_text) % 16 != 0: padding_count = 16 - len(plain_text) % 16 plain_text += os.urandom(padding_count) @@ -50,8 +54,9 @@ class AES: blocks_count = len(plain_text) // 16 for block_index in range(blocks_count): - plain_text_block = list(plain_text[block_index * 16:block_index * - 16 + 16]) + plain_text_block = list( + plain_text[block_index * 16:block_index * 16 + 16] + ) for i in range(16): plain_text_block[i] ^= iv1[i] @@ -60,9 +65,9 @@ class AES: for i in range(16): cipher_text_block[i] ^= iv2[i] - iv1 = cipher_text_block[:] + iv1 = cipher_text_block iv2 = plain_text[block_index * 16:block_index * 16 + 16] - cipher_text.extend(cipher_text_block[:]) + cipher_text.extend(cipher_text_block) return bytes(cipher_text)