Telethon/telethon/network/connection/tcpobfuscated.py
2019-01-11 15:52:30 +01:00

52 lines
1.8 KiB
Python

import os
from .tcpabridged import ConnectionTcpAbridged
from ...crypto import AESModeCTR
class ConnectionTcpObfuscated(ConnectionTcpAbridged):
"""
Encodes the packet just like `ConnectionTcpAbridged`, but encrypts
every message with a randomly generated key using the
AES-CTR mode so the packets are harder to discern.
"""
def __init__(self, ip, port, *, loop, loggers, proxy=None):
super().__init__(ip, port, loop=loop, loggers=loggers, proxy=proxy)
self._aes_encrypt = None
self._aes_decrypt = None
def _write(self, data):
self._writer.write(self._aes_encrypt.encrypt(data))
async def _read(self, n):
return self._aes_decrypt.encrypt(await self._reader.readexactly(n))
async def connect(self, timeout=None, ssl=None):
await super().connect(timeout=timeout, ssl=ssl)
# Obfuscated messages secrets cannot start with any of these
keywords = (b'PVrG', b'GET ', b'POST', b'\xee\xee\xee\xee')
while True:
random = os.urandom(64)
if (random[0] != b'\xef' and
random[:4] not in keywords and
random[4:4] != b'\0\0\0\0'):
break
random = bytearray(random)
random[56] = random[57] = random[58] = random[59] = 0xef
random_reversed = random[55:7:-1] # Reversed (8, len=48)
# Encryption has "continuous buffer" enabled
encrypt_key = bytes(random[8:40])
encrypt_iv = bytes(random[40:56])
decrypt_key = bytes(random_reversed[:32])
decrypt_iv = bytes(random_reversed[32:48])
self._aes_encrypt = AESModeCTR(encrypt_key, encrypt_iv)
self._aes_decrypt = AESModeCTR(decrypt_key, decrypt_iv)
random[56:64] = self._aes_encrypt.encrypt(bytes(random))[56:64]
self._writer.write(random)
await self._writer.drain()