Law/app/services/invoice_crypto.py
2026-02-23 17:54:19 +03:00

56 lines
2 KiB
Python

from __future__ import annotations
import base64
import hashlib
import hmac
import json
import secrets
from typing import Any
from app.core.config import settings
_VERSION = b"v1"
def _key() -> bytes:
secret = str(settings.DATA_ENCRYPTION_SECRET or "").strip()
if not secret or secret == "change_me_data_encryption":
secret = str(settings.ADMIN_JWT_SECRET or "change_me_admin")
return hashlib.sha256(secret.encode("utf-8")).digest()
def _xor_bytes(a: bytes, b: bytes) -> bytes:
return bytes(x ^ y for x, y in zip(a, b))
def encrypt_requisites(data: dict[str, Any] | None) -> str:
payload = dict(data or {})
raw = json.dumps(payload, ensure_ascii=False, separators=(",", ":")).encode("utf-8")
nonce = secrets.token_bytes(16)
stream = hashlib.pbkdf2_hmac("sha256", _key(), nonce, 120_000, dklen=len(raw))
cipher = _xor_bytes(raw, stream)
tag = hmac.new(_key(), _VERSION + nonce + cipher, hashlib.sha256).digest()
token = _VERSION + nonce + tag + cipher
return base64.urlsafe_b64encode(token).decode("ascii")
def decrypt_requisites(token: str | None) -> dict[str, Any]:
encoded = str(token or "").strip()
if not encoded:
return {}
blob = base64.urlsafe_b64decode(encoded.encode("ascii"))
if len(blob) < 2 + 16 + 32:
raise ValueError("Некорректные зашифрованные реквизиты")
version = blob[:2]
nonce = blob[2:18]
tag = blob[18:50]
cipher = blob[50:]
if version != _VERSION:
raise ValueError("Неподдерживаемая версия шифрования")
expected = hmac.new(_key(), version + nonce + cipher, hashlib.sha256).digest()
if not hmac.compare_digest(tag, expected):
raise ValueError("Поврежденные зашифрованные реквизиты")
stream = hashlib.pbkdf2_hmac("sha256", _key(), nonce, 120_000, dklen=len(cipher))
raw = _xor_bytes(cipher, stream)
data = json.loads(raw.decode("utf-8"))
return data if isinstance(data, dict) else {}