diff --git a/cryptography/hazmat/backends/interfaces.py b/cryptography/hazmat/backends/interfaces.py
index 912476b..9a57096 100644
--- a/cryptography/hazmat/backends/interfaces.py
+++ b/cryptography/hazmat/backends/interfaces.py
@@ -60,6 +60,13 @@
 
 class HMACBackend(six.with_metaclass(abc.ABCMeta)):
     @abc.abstractmethod
+    def hmac_supported(self, algorithm):
+        """
+        Return True if the hash algorithm is supported for HMAC by this
+        backend.
+        """
+
+    @abc.abstractmethod
     def create_hmac_ctx(self, key, algorithm):
         """
         Create a HashContext for calculating a message authentication code.
diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index 45fbaf0..5b6cd64 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -141,8 +141,8 @@
 
         Create a
         :class:`~cryptogrpahy.hazmat.primitives.interfaces.HashContext` that
-            uses the specified ``algorithm`` to calculate a hash-based message
-            authentication code.
+        uses the specified ``algorithm`` to calculate a hash-based message
+        authentication code.
 
         :param algorithm: An instance of a
             :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`