62 lines
2.0 KiB
Python
62 lines
2.0 KiB
Python
# Pyrogram - Telegram MTProto API Client Library for Python
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# Copyright (C) 2017 Dan Tès <https://github.com/delivrance>
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#
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# This file is part of Pyrogram.
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#
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# Pyrogram is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published
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# by the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# Pyrogram is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with Pyrogram. If not, see <http://www.gnu.org/licenses/>.
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from pyaes import AES
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BLOCK_SIZE = 16
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# TODO: Performance optimization
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class IGE:
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@classmethod
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def encrypt(cls, data: bytes, key: bytes, iv: bytes) -> bytes:
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return cls.ige(data, key, iv, True)
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@classmethod
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def decrypt(cls, data: bytes, key: bytes, iv: bytes) -> bytes:
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return cls.ige(data, key, iv, False)
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@staticmethod
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def xor(a: bytes, b: bytes) -> bytes:
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return int.to_bytes(
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int.from_bytes(a, "big") ^ int.from_bytes(b, "big"),
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len(a),
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"big",
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)
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@classmethod
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def ige(cls, data: bytes, key: bytes, iv: bytes, encrypt: bool) -> bytes:
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cipher = AES(key)
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iv_1 = iv[:BLOCK_SIZE]
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iv_2 = iv[BLOCK_SIZE:]
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data = [data[i: i + BLOCK_SIZE] for i in range(0, len(data), BLOCK_SIZE)]
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if encrypt:
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for i, chunk in enumerate(data):
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iv_1 = data[i] = cls.xor(cipher.encrypt(cls.xor(chunk, iv_1)), iv_2)
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iv_2 = chunk
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else:
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for i, chunk in enumerate(data):
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iv_2 = data[i] = cls.xor(cipher.decrypt(cls.xor(chunk, iv_2)), iv_1)
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iv_1 = chunk
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return b"".join(data)
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