Telethon/telethon/_crypto/authkey.py
2021-09-12 16:23:55 +02:00

64 lines
1.9 KiB
Python

"""
This module holds the AuthKey class.
"""
import struct
from hashlib import sha1
from .._misc.binaryreader import BinaryReader
class AuthKey:
"""
Represents an authorization key, used to encrypt and decrypt
messages sent to Telegram's data centers.
"""
def __init__(self, data):
"""
Initializes a new authorization key.
:param data: the data in bytes that represent this auth key.
"""
self.key = data
@property
def key(self):
return self._key
@key.setter
def key(self, value):
if not value:
self._key = self.aux_hash = self.key_id = None
return
if isinstance(value, type(self)):
self._key, self.aux_hash, self.key_id = \
value._key, value.aux_hash, value.key_id
return
self._key = value
with BinaryReader(sha1(self._key).digest()) as reader:
self.aux_hash = reader.read_long(signed=False)
reader.read(4)
self.key_id = reader.read_long(signed=False)
# TODO This doesn't really fit here, it's only used in authentication
def calc_new_nonce_hash(self, new_nonce, number):
"""
Calculates the new nonce hash based on the current attributes.
:param new_nonce: the new nonce to be hashed.
:param number: number to prepend before the hash.
:return: the hash for the given new nonce.
"""
new_nonce = new_nonce.to_bytes(32, 'little', signed=True)
data = new_nonce + struct.pack('<BQ', number, self.aux_hash)
# Calculates the message key from the given data
return int.from_bytes(sha1(data).digest()[4:20], 'little', signed=True)
def __bool__(self):
return bool(self._key)
def __eq__(self, other):
return isinstance(other, type(self)) and other.key == self._key