2 files changed, 65 insertions, 0 deletions
diff --git a/cryptography/hazmat/bindings/interfaces.py b/cryptography/hazmat/bindings/interfaces.py
new file mode 100644
index 00000000..ffcd5f14
--- /dev/null
+++ b/cryptography/hazmat/bindings/interfaces.py
@@ -0,0 +1,59 @@
+# 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 absolute_import, division, print_function
+
+import abc
+
+import six
+
+
+class CipherBackend(six.with_metaclass(abc.ABCMeta)):
+    @abc.abstractmethod
+    def cipher_supported(self, cipher, mode):
+        """
+        """
+
+    @abc.abstractmethod
+    def register_cipher_adapter(self, cipher, mode):
+        """
+        """
+
+    @abc.abstractmethod
+    def create_symmetric_encryption_ctx(self, cipher, mode):
+        """
+        """
+
+    @abc.abstractmethod
+    def create_symmetric_decryption_ctx(self, cipher, mode):
+        """
+        """
+
+
+class HashBackend(six.with_metaclass(abc.ABCMeta)):
+    @abc.abstractmethod
+    def hash_supported(self, algorithm):
+        """
+        """
+
+    @abc.abstractmethod
+    def create_hash_ctx(self, algorithm):
+        """
+        """
+
+
+class HMACBackend(six.with_metaclass(abc.ABCMeta)):
+    @abc.abstractmethod
+    def create_hmac_ctx(self, key, algorithm):
+        """
+        """
diff --git a/cryptography/hazmat/bindings/openssl/backend.py b/cryptography/hazmat/bindings/openssl/backend.py
index 92cd3868..db4d18e7 100644
--- a/cryptography/hazmat/bindings/openssl/backend.py
+++ b/cryptography/hazmat/bindings/openssl/backend.py
@@ -20,6 +20,9 @@ import cffi
 
 from cryptography import utils
 from cryptography.exceptions import UnsupportedAlgorithm
+from cryptography.hazmat.bindings.interfaces import (
+    CipherBackend, HashBackend, HMACBackend
+)
 from cryptography.hazmat.primitives import interfaces
 from cryptography.hazmat.primitives.ciphers.algorithms import (
     AES, Blowfish, Camellia, CAST5, TripleDES, ARC4,
@@ -29,6 +32,9 @@ from cryptography.hazmat.primitives.ciphers.modes import (
 )
 
 
+@utils.register_interface(CipherBackend)
+@utils.register_interface(HashBackend)
+@utils.register_interface(HMACBackend)
 class Backend(object):
     """
     OpenSSL API wrapper.