mirror of
https://github.com/TronoSfera/Law.git
synced 2026-05-18 18:13:46 +03:00
126 lines
4.5 KiB
Python
126 lines
4.5 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 json
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import secrets
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from typing import Any
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from app.services.crypto_keyring import get_data_secrets, key_digest, ordered_unique_key_digests
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_VERSION_LEGACY = b"v1"
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_PREFIX_V2 = "invenc:v2:"
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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 _aad_v2(kid: str) -> bytes:
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return b"v2|" + str(kid).encode("utf-8") + b"|"
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def active_requisites_kid() -> str:
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active_kid, _ = get_data_secrets()
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return active_kid
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def extract_requisites_kid(token: str | None) -> str | None:
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encoded = str(token or "").strip()
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if not encoded:
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return None
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if not encoded.startswith(_PREFIX_V2):
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return None
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parts = encoded.split(":", 3)
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if len(parts) != 4:
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return None
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kid = str(parts[2] or "").strip()
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return kid or None
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def _encrypt_payload(raw: bytes, *, kid: str, key: bytes) -> str:
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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, _aad_v2(kid) + nonce + cipher, hashlib.sha256).digest()
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token = nonce + tag + cipher
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encoded = base64.urlsafe_b64encode(token).decode("ascii")
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return f"{_PREFIX_V2}{kid}:{encoded}"
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def _decrypt_v2(encoded: str, *, kid: str, key: bytes) -> dict[str, Any]:
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blob = base64.urlsafe_b64decode(encoded.encode("ascii"))
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if len(blob) < 16 + 32:
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raise ValueError("Некорректные зашифрованные реквизиты")
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nonce = blob[:16]
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tag = blob[16:48]
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cipher = blob[48:]
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expected = hmac.new(key, _aad_v2(kid) + nonce + cipher, hashlib.sha256).digest()
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if not hmac.compare_digest(tag, expected):
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raise ValueError("Поврежденные зашифрованные реквизиты")
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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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data = json.loads(raw.decode("utf-8"))
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return data if isinstance(data, dict) else {}
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def _decrypt_legacy(token: str, keys: list[bytes]) -> dict[str, Any]:
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blob = base64.urlsafe_b64decode(token.encode("ascii"))
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if len(blob) < 2 + 16 + 32:
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raise ValueError("Некорректные зашифрованные реквизиты")
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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_LEGACY:
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raise ValueError("Неподдерживаемая версия шифрования")
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for key in keys:
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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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continue
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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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data = json.loads(raw.decode("utf-8"))
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return data if isinstance(data, dict) else {}
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raise ValueError("Поврежденные зашифрованные реквизиты")
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def encrypt_requisites(data: dict[str, Any] | None) -> str:
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payload = dict(data or {})
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raw = json.dumps(payload, ensure_ascii=False, separators=(",", ":")).encode("utf-8")
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active_kid, key_map = get_data_secrets()
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active_secret = key_map.get(active_kid)
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if not active_secret:
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raise ValueError("Не найден активный ключ шифрования DATA")
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return _encrypt_payload(raw, kid=active_kid, key=key_digest(active_secret))
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def decrypt_requisites(token: str | None) -> dict[str, Any]:
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encoded = str(token or "").strip()
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if not encoded:
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return {}
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active_kid, key_map = get_data_secrets()
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_ = active_kid
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if encoded.startswith(_PREFIX_V2):
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parts = encoded.split(":", 3)
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if len(parts) != 4:
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raise ValueError("Некорректные зашифрованные реквизиты")
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kid = str(parts[2] or "").strip()
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payload = parts[3]
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if kid in key_map:
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return _decrypt_v2(payload, kid=kid, key=key_digest(key_map[kid]))
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for fallback_key in ordered_unique_key_digests(key_map.values()):
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try:
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return _decrypt_v2(payload, kid=kid, key=fallback_key)
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except Exception:
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continue
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raise ValueError("Неподдерживаемый идентификатор ключа шифрования")
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return _decrypt_legacy(encoded, ordered_unique_key_digests(key_map.values()))
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