add basic multibackend so we can do signatures using default_backend

1 files changed, 7 insertions, 0 deletions

diff --git a/cryptography/hazmat/backends/multibackend.py b/cryptography/hazmat/backends/multibackend.py
index 4de02026..eb58dd68 100644
--- a/cryptography/hazmat/backends/multibackend.py
+++ b/cryptography/hazmat/backends/multibackend.py
@@ -24,6 +24,7 @@ from cryptography.hazmat.backends.interfaces import (
 @utils.register_interface(HashBackend)
 @utils.register_interface(HMACBackend)
 @utils.register_interface(PBKDF2HMACBackend)
+@utils.register_interface(RSABackend)
 class MultiBackend(object):
     name = "multibackend"
 
@@ -106,3 +107,9 @@ class MultiBackend(object):
         for b in self._filtered_backends(RSABackend):
             return b.generate_rsa_private_key(public_exponent, key_size)
         raise UnsupportedAlgorithm
+
+    def create_rsa_signature_ctx(self, private_key, padding, algorithm):
+        for b in self._filtered_backends(RSABackend):
+            return b.create_rsa_signature_ctx(private_key, padding, algorithm)
+        raise UnsupportedAlgorithm
+