Telethon/utils/aes.py
2016-09-03 20:34:24 +02:00

62 lines
1.8 KiB
Python

import pyaes
class AES:
@staticmethod
def decrypt_ige(cipher_text, key, iv):
iv1 = iv[:len(iv)//2]
iv2 = iv[len(iv)//2:]
aes = pyaes.AES(key)
plain_text = [0] * len(cipher_text)
blocks_count = len(cipher_text) // 16
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]
plain_text_block = aes.decrypt(cipher_text_block)
for i in range(16):
plain_text_block[i] ^= iv1[i]
iv1 = cipher_text[block_index * 16:block_index * 16 + 16]
iv2 = plain_text_block[0:16]
plain_text[block_index * 16:block_index * 16 + 16] = plain_text_block[:16]
return bytes(plain_text)
@staticmethod
def encrypt_ige(plain_text, key, iv):
# TODO: Random padding
padding = bytes(16 - len(plain_text) % 16)
plain_text += padding
iv1 = iv[:len(iv)//2]
iv2 = iv[len(iv)//2:]
aes = pyaes.AES(key)
blocks_count = len(plain_text) // 16
cipher_text = [0] * len(plain_text)
for block_index in range(blocks_count):
plain_text_block = list(plain_text[block_index * 16:block_index * 16 + 16])
for i in range(16):
plain_text_block[i] ^= iv1[i]
cipher_text_block = aes.encrypt(plain_text_block)
for i in range(16):
cipher_text_block[i] ^= iv2[i]
iv1 = cipher_text_block[0:16]
iv2 = plain_text[block_index * 16:block_index * 16 + 16]
cipher_text[block_index * 16:block_index * 16 + 16] = cipher_text_block[:16]
return bytes(cipher_text)