HashBackend is now supported by PrioritizedMultiBackend

1 files changed, 13 insertions, 1 deletions

diff --git a/cryptography/hazmat/backends/multibackend.py b/cryptography/hazmat/backends/multibackend.py
index 9b91ff45..210efbe8 100644
--- a/cryptography/hazmat/backends/multibackend.py
+++ b/cryptography/hazmat/backends/multibackend.py
@@ -15,10 +15,11 @@ from __future__ import absolute_import, division, print_function
 
 from cryptography import utils
 from cryptography.exceptions import UnsupportedAlgorithm
-from cryptography.hazmat.backends.interfaces import CipherBackend
+from cryptography.hazmat.backends.interfaces import CipherBackend, HashBackend
 
 
 @utils.register_interface(CipherBackend)
+@utils.register_interface(HashBackend)
 class PrioritizedMultiBackend(object):
     name = "multibackend"
 
@@ -43,3 +44,14 @@ class PrioritizedMultiBackend(object):
             except UnsupportedAlgorithm:
                 pass
         raise UnsupportedAlgorithm
+
+    def hash_supported(self, algorithm):
+        return any(b.hash_supported(algorithm) for b in self._backends)
+
+    def create_hash_ctx(self, algorithm):
+        for b in self._backends:
+            try:
+                return b.create_hash_ctx(algorithm)
+            except UnsupportedAlgorithm:
+                pass
+        raise UnsupportedAlgorithm