Telethon/telethon/helpers.py
2017-09-04 17:10:04 +02:00

74 lines
2.1 KiB
Python

"""Various helpers not related to the Telegram API itself"""
from hashlib import sha1, sha256
import os
# region Multiple utilities
def generate_random_long(signed=True):
"""Generates a random long integer (8 bytes), which is optionally signed"""
return int.from_bytes(os.urandom(8), signed=signed, byteorder='little')
def ensure_parent_dir_exists(file_path):
"""Ensures that the parent directory exists"""
parent = os.path.dirname(file_path)
if parent:
os.makedirs(parent, exist_ok=True)
# endregion
# region Cryptographic related utils
def calc_key(shared_key, msg_key, client):
"""Calculate the key based on Telegram guidelines,
specifying whether it's the client or not
"""
x = 0 if client else 8
sha1a = sha1(msg_key + shared_key[x:x + 32]).digest()
sha1b = sha1(shared_key[x + 32:x + 48] + msg_key +
shared_key[x + 48:x + 64]).digest()
sha1c = sha1(shared_key[x + 64:x + 96] + msg_key).digest()
sha1d = sha1(msg_key + shared_key[x + 96:x + 128]).digest()
key = sha1a[0:8] + sha1b[8:20] + sha1c[4:16]
iv = sha1a[8:20] + sha1b[0:8] + sha1c[16:20] + sha1d[0:8]
return key, iv
def calc_msg_key(data):
"""Calculates the message key from the given data"""
return sha1(data).digest()[4:20]
def generate_key_data_from_nonce(server_nonce, new_nonce):
"""Generates the key data corresponding to the given nonce"""
hash1 = sha1(bytes(new_nonce + server_nonce)).digest()
hash2 = sha1(bytes(server_nonce + new_nonce)).digest()
hash3 = sha1(bytes(new_nonce + new_nonce)).digest()
key = hash1 + hash2[:12]
iv = hash2[12:20] + hash3 + new_nonce[:4]
return key, iv
def get_password_hash(pw, current_salt):
"""Gets the password hash for the two-step verification.
current_salt should be the byte array provided by
invoking GetPasswordRequest()
"""
# Passwords are encoded as UTF-8
# At https://github.com/DrKLO/Telegram/blob/e31388
# src/main/java/org/telegram/ui/LoginActivity.java#L2003
data = pw.encode('utf-8')
pw_hash = current_salt + data + current_salt
return sha256(pw_hash).digest()
# endregion