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mautrix-telegram/mautrix_telegram/util/signed_token.py
T

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Python

# -*- coding: future_fstrings -*-
# mautrix-telegram - A Matrix-Telegram puppeting bridge
# Copyright (C) 2018 Tulir Asokan
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
from typing import Dict, Optional
import json
import base64
import hashlib
def _get_checksum(key: str, payload: bytes) -> str:
hasher = hashlib.sha256()
hasher.update(payload)
hasher.update(key.encode("utf-8"))
checksum = hasher.hexdigest()
return checksum
def sign_token(key: str, payload: Dict) -> str:
payload_b64 = base64.urlsafe_b64encode(json.dumps(payload).encode("utf-8"))
checksum = _get_checksum(key, payload_b64)
return f"{checksum}:{payload_b64.decode('utf-8')}"
def verify_token(key: str, data: str) -> Optional[Dict]:
if not data:
return None
try:
checksum, payload = data.split(":", 1)
except ValueError:
return None
if checksum != _get_checksum(key, payload.encode("utf-8")):
return None
payload = base64.urlsafe_b64decode(payload).decode("utf-8")
try:
return json.loads(payload)
except json.JSONDecodeError:
return None