| """AES-256-GCM encryption for the WhatsApp session stored in the database.""" |
|
|
| from __future__ import annotations |
|
|
| import base64 |
| import hashlib |
| import os |
|
|
| from cryptography.hazmat.primitives.ciphers.aead import AESGCM |
|
|
| PREFIX = "enc:v1:" |
|
|
|
|
| class Sealer: |
| def __init__(self, key: str): |
| self._aes = AESGCM(hashlib.sha256(key.encode("utf-8")).digest()) |
|
|
| def seal(self, data: bytes) -> str: |
| nonce = os.urandom(12) |
| ciphertext = self._aes.encrypt(nonce, data, None) |
| return PREFIX + base64.b64encode(nonce + ciphertext).decode("ascii") |
|
|
| def open(self, value: str) -> bytes: |
| if not value.startswith(PREFIX): |
| raise ValueError("stored session is not encrypted") |
| raw = base64.b64decode(value[len(PREFIX):]) |
| return self._aes.decrypt(raw[:12], raw[12:], None) |
|
|
