1# Copyright 2017 Google LLC
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#      http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15"""RSA cryptography signer and verifier."""
16
17
18try:
19    # Prefer cryptograph-based RSA implementation.
20    from google.auth.crypt import _cryptography_rsa
21
22    RSASigner = _cryptography_rsa.RSASigner
23    RSAVerifier = _cryptography_rsa.RSAVerifier
24except ImportError:  # pragma: NO COVER
25    # Fallback to pure-python RSA implementation if cryptography is
26    # unavailable.
27    from google.auth.crypt import _python_rsa
28
29    RSASigner = _python_rsa.RSASigner
30    RSAVerifier = _python_rsa.RSAVerifier
31