mirror of
https://github.com/LonamiWebs/Telethon.git
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62 lines
1.7 KiB
Python
62 lines
1.7 KiB
Python
import random
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from utils.binary_writer import BinaryWriter
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from hashlib import sha1
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def generate_random_long(signed=True):
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"""Generates a random long integer (8 bytes), which is optionally signed"""
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result = random.getrandbits(64)
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if not signed:
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result &= 0xFFFFFFFFFFFFFFFF # Ensure it's unsigned
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return result
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def generate_random_bytes(count):
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"""Generates a random bytes array"""
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with BinaryWriter() as writer:
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for _ in range(count):
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writer.write(random.getrandbits(8))
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return writer.get_bytes()
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def calc_key(shared_key, msg_key, client):
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"""Calculate the key based on Telegram guidelines, specifying whether it's the client or not"""
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x = 0 if client else 8
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buffer = [0] * 48
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buffer[0:16] = msg_key
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buffer[16:48] = shared_key[x:x + 32]
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sha1a = sha1(buffer)
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buffer[0:16] = shared_key[x + 32:x + 48]
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buffer[16:32] = msg_key
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buffer[32:48] = shared_key[x + 48:x + 64]
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sha1b = sha1(buffer)
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buffer[0:32] = shared_key[x + 64:x + 96]
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buffer[32:48] = msg_key
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sha1c = sha1(buffer)
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buffer[0:16] = msg_key
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buffer[16:48] = shared_key[x + 96:x + 128]
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sha1d = sha1(buffer)
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key = sha1a[0:8] + sha1b[8:20] + sha1c[4:16]
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iv = sha1a[8:20] + sha1b[0:8] + sha1c[16:20] + sha1d[0:8]
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return key, iv
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def calc_msg_key(data):
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"""Calculates the message key from the given data"""
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return sha1(data)[4:20]
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def calc_msg_key_offset(data, offset, limit):
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"""Calculates the message key from offset given data, with an optional offset and limit"""
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# TODO untested, may not be offset like this
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# In the original code it was as parameters for the sha function, not slicing the array
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return sha1(data[offset:offset + limit])[4:20]
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