1 files changed, 30 insertions, 0 deletions
diff --git a/google/auth/crypt/rsa.py b/google/auth/crypt/rsa.py
new file mode 100644
index 0000000..8b2d64c
--- /dev/null
+++ b/google/auth/crypt/rsa.py
@@ -0,0 +1,30 @@
+# Copyright 2017 Google LLC
+#
+# 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.
+
+"""RSA cryptography signer and verifier."""
+
+
+try:
+    # Prefer cryptograph-based RSA implementation.
+    from google.auth.crypt import _cryptography_rsa
+
+    RSASigner = _cryptography_rsa.RSASigner
+    RSAVerifier = _cryptography_rsa.RSAVerifier
+except ImportError:  # pragma: NO COVER
+    # Fallback to pure-python RSA implementation if cryptography is
+    # unavailable.
+    from google.auth.crypt import _python_rsa
+
+    RSASigner = _python_rsa.RSASigner
+    RSAVerifier = _python_rsa.RSAVerifier