mirror of
https://github.com/TronoSfera/Law.git
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83 lines
2.6 KiB
Python
83 lines
2.6 KiB
Python
from __future__ import annotations
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import base64
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import hashlib
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import hmac
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import secrets
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from app.core.config import settings
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_VERSION = b"v1"
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_PREFIX = "chatenc:v1:"
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def _encryption_secret() -> str:
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chat_secret = str(settings.CHAT_ENCRYPTION_SECRET or "").strip()
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if chat_secret:
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return chat_secret
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fallback = str(settings.DATA_ENCRYPTION_SECRET or "").strip()
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if fallback:
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return fallback
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fallback = str(settings.ADMIN_JWT_SECRET or "").strip()
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if fallback:
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return fallback
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fallback = str(settings.PUBLIC_JWT_SECRET or "").strip()
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if fallback:
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return fallback
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raise ValueError("Не задан секрет шифрования чата")
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def _key() -> bytes:
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return hashlib.sha256(_encryption_secret().encode("utf-8")).digest()
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def _xor_bytes(a: bytes, b: bytes) -> bytes:
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return bytes(x ^ y for x, y in zip(a, b))
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def is_encrypted_message(value: str | None) -> bool:
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token = str(value or "").strip()
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return token.startswith(_PREFIX)
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def encrypt_message_body(value: str | None) -> str | None:
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if value is None:
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return None
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text = str(value)
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if not text:
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return text
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if is_encrypted_message(text):
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return text
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raw = text.encode("utf-8")
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nonce = secrets.token_bytes(16)
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stream = hashlib.pbkdf2_hmac("sha256", _key(), nonce, 120_000, dklen=len(raw))
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cipher = _xor_bytes(raw, stream)
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tag = hmac.new(_key(), _VERSION + nonce + cipher, hashlib.sha256).digest()
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token = _VERSION + nonce + tag + cipher
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return _PREFIX + base64.urlsafe_b64encode(token).decode("ascii")
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def decrypt_message_body(value: str | None) -> str | None:
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if value is None:
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return None
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text = str(value)
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if not text:
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return text
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if not is_encrypted_message(text):
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return text
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encoded = text[len(_PREFIX) :]
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blob = base64.urlsafe_b64decode(encoded.encode("ascii"))
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if len(blob) < 2 + 16 + 32:
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raise ValueError("Некорректный зашифрованный формат сообщения")
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version = blob[:2]
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nonce = blob[2:18]
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tag = blob[18:50]
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cipher = blob[50:]
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if version != _VERSION:
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raise ValueError("Неподдерживаемая версия шифрования чата")
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expected = hmac.new(_key(), version + nonce + cipher, hashlib.sha256).digest()
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if not hmac.compare_digest(tag, expected):
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raise ValueError("Поврежденные данные сообщения")
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stream = hashlib.pbkdf2_hmac("sha256", _key(), nonce, 120_000, dklen=len(cipher))
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raw = _xor_bytes(cipher, stream)
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return raw.decode("utf-8")
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