使用 Google 公開金鑰加密客戶私密金鑰

這個範例示範如何使用 Google 公開金鑰加密客戶私密金鑰，確保只有 Google 可以解密。

深入探索

如需包含這個程式碼範例的詳細說明文件，請參閱下列內容：

程式碼範例

Python

在試用這個範例之前，請先按照Python「使用用戶端程式庫的 Compute Engine 快速入門」中的操作說明進行設定。詳情請參閱 Compute Engine Python API 參考說明文件。

如要向 Compute Engine 進行驗證，請設定應用程式預設憑證。 詳情請參閱「為本機開發環境設定驗證」。

import argparse
import base64
import os
from typing import Optional

from cryptography import x509
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives.asymmetric.rsa import RSAPublicKey
import requests


GOOGLE_PUBLIC_CERT_URL = (
    "https://cloud-certs.storage.googleapis.com/google-cloud-csek-ingress.pem"
)


def get_google_public_cert_key() -> RSAPublicKey:
    """
    Downloads the Google public certificate.

    Returns:
        RSAPublicKey object with the Google public certificate.
    """
    r = requests.get(GOOGLE_PUBLIC_CERT_URL)
    r.raise_for_status()

    # Load the certificate.
    certificate = x509.load_pem_x509_certificate(r.content, default_backend())

    # Get the certicate's public key.
    public_key = certificate.public_key()

    return public_key


def wrap_rsa_key(public_key: RSAPublicKey, private_key_bytes: bytes) -> bytes:
    """
    Use the Google public key to encrypt the customer private key.

    This means that only the Google private key is capable of decrypting
    the customer private key.

    Args:
        public_key: The public key to use for encrypting.
        private_key_bytes: The private key to be encrypted.

    Returns:
        private_key_bytes encrypted using the public_key. Encoded using
        base64.
    """
    wrapped_key = public_key.encrypt(
        private_key_bytes,
        padding.OAEP(
            mgf=padding.MGF1(algorithm=hashes.SHA1()),
            algorithm=hashes.SHA1(),
            label=None,
        ),
    )
    encoded_wrapped_key = base64.b64encode(wrapped_key)
    return encoded_wrapped_key


def main(key_file: Optional[str]) -> None:
    """
    This script will encrypt a private key with Google public key.

    Args:
        key_file: path to a file containing your private key. If not
            provided, a new key will be generated (256 bit).
    """
    # Generate a new 256-bit private key if no key is specified.
    if not key_file:
        customer_key_bytes = os.urandom(32)
    else:
        with open(key_file, "rb") as f:
            customer_key_bytes = f.read()

    google_public_key = get_google_public_cert_key()
    wrapped_rsa_key = wrap_rsa_key(google_public_key, customer_key_bytes)

    b64_key = base64.b64encode(customer_key_bytes).decode("utf-8")

    print(f"Base-64 encoded private key: {b64_key}")
    print(f"Wrapped RSA key: {wrapped_rsa_key.decode('utf-8')}")


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter
    )
    parser.add_argument("--key_file", help="File containing your binary private key.")

    args = parser.parse_args()

    main(args.key_file)

後續步驟

如要搜尋及篩選其他 Google Cloud 產品的程式碼範例，請參閱Google Cloud 範例瀏覽器。