Adding compute engine private key generation sample.

Change-Id: I06ba22294f8f0d734b048b3e903d2f98178b4a5c

Author: Jon Wayne Parrott

compute/encryption/generate_wrapped_rsa_key.py

@@ -0,0 +1,93 @@
+#!/usr/bin/env python
+
+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# 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.
+
+"""Example of authenticating using access tokens directly on Compute Engine.
+
+For more information, see the README.md under /compute.
+"""
+
+# [START all]
+
+import argparse
+import base64
+import os
+
+from cryptography import x509
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.asymmetric import padding
+import requests
+
+
+GOOGLE_PUBLIC_CERT_URL = (
+    'https://cloud-certs.storage.googleapis.com/google-cloud-csek-ingress.pem')
+
+
+def get_google_public_cert_key():
+    r = requests.get(GOOGLE_PUBLIC_CERT_URL)
+    r.raise_for_status()
+
+    # Load the certificate.
+    certificate = x509.load_pem_x509_certificate(
+        r.text.encode('utf-8'), default_backend())
+
+    # Get the certicate's public key.
+    public_key = certificate.public_key()
+
+    return public_key
+
+
+def wrap_rsa_key(public_key, private_key_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.
+    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):
+    # 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)
+
+    print('Base-64 encoded private key: {}'.format(
+        base64.b64encode(customer_key_bytes).decode('utf-8')))
+    print('Wrapped RSA key: {}'.format(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)
+# [END all]

compute/encryption/generate_wrapped_rsa_key_test.py

@@ -0,0 +1,18 @@
+# Copyright 2016, Google, Inc.
+# 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.
+
+import generate_wrapped_rsa_key
+
+
+def test_main():
+    generate_wrapped_rsa_key.main()

compute/encryption/requirements.txt

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+cryptography==1.3.1
+requests==2.9.1