crypto_utils.py

# -*- coding: utf-8 -*-

"""
Copyright 2026 The Dapr Authors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""

from __future__ import annotations

import secrets
from pathlib import Path

from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import rsa

RSA_KEY_FILENAME = 'rsa-private-key.pem'
SYMMETRIC_KEY_FILENAME = 'symmetric-key-256'

_RSA_KEY_SIZE = 4096
_SYMMETRIC_KEY_BYTES = 32


def write_test_keys(target_dir: Path) -> None:
    """Write a fresh RSA private key (PKCS8 PEM) and a 256-bit AES key.

    File names match those expected by ``examples/crypto/crypto.py`` and the
    ``cryptostore.yaml`` component used by the integration tests.
    """
    target_dir.mkdir(parents=True, exist_ok=True)

    rsa_key = rsa.generate_private_key(public_exponent=65537, key_size=_RSA_KEY_SIZE)
    rsa_pem = rsa_key.private_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PrivateFormat.PKCS8,
        encryption_algorithm=serialization.NoEncryption(),
    )
    (target_dir / RSA_KEY_FILENAME).write_bytes(rsa_pem)
    (target_dir / SYMMETRIC_KEY_FILENAME).write_bytes(secrets.token_bytes(_SYMMETRIC_KEY_BYTES))


def remove_test_keys(target_dir: Path) -> None:
    for name in (RSA_KEY_FILENAME, SYMMETRIC_KEY_FILENAME):
        (target_dir / name).unlink(missing_ok=True)