Convert stuff

2 files changed, 15 insertions, 13 deletions

diff --git a/cryptography/hazmat/backends/multibackend.py b/cryptography/hazmat/backends/multibackend.py
index de1fff7c..cca82a59 100644
--- a/cryptography/hazmat/backends/multibackend.py
+++ b/cryptography/hazmat/backends/multibackend.py
@@ -14,7 +14,9 @@
 from __future__ import absolute_import, division, print_function
 
 from cryptography import utils
-from cryptography.exceptions import UnsupportedAlgorithm
+from cryptography.exceptions import (
+    UnsupportedAlgorithm, UnsupportedCipher, UnsupportedHash
+)
 from cryptography.hazmat.backends.interfaces import (
     CipherBackend, HashBackend, HMACBackend, PBKDF2HMACBackend, RSABackend
 )
@@ -46,17 +48,17 @@ class MultiBackend(object):
         for b in self._filtered_backends(CipherBackend):
             try:
                 return b.create_symmetric_encryption_ctx(algorithm, mode)
-            except UnsupportedAlgorithm:
+            except UnsupportedCipher:
                 pass
-        raise UnsupportedAlgorithm
+        raise UnsupportedCipher
 
     def create_symmetric_decryption_ctx(self, algorithm, mode):
         for b in self._filtered_backends(CipherBackend):
             try:
                 return b.create_symmetric_decryption_ctx(algorithm, mode)
-            except UnsupportedAlgorithm:
+            except UnsupportedCipher:
                 pass
-        raise UnsupportedAlgorithm
+        raise UnsupportedCipher
 
     def hash_supported(self, algorithm):
         return any(
@@ -68,9 +70,9 @@ class MultiBackend(object):
         for b in self._filtered_backends(HashBackend):
             try:
                 return b.create_hash_ctx(algorithm)
-            except UnsupportedAlgorithm:
+            except UnsupportedHash:
                 pass
-        raise UnsupportedAlgorithm
+        raise UnsupportedHash
 
     def hmac_supported(self, algorithm):
         return any(
@@ -82,9 +84,9 @@ class MultiBackend(object):
         for b in self._filtered_backends(HMACBackend):
             try:
                 return b.create_hmac_ctx(key, algorithm)
-            except UnsupportedAlgorithm:
+            except UnsupportedHash:
                 pass
-        raise UnsupportedAlgorithm
+        raise UnsupportedHash
 
     def pbkdf2_hmac_supported(self, algorithm):
         return any(
@@ -99,9 +101,9 @@ class MultiBackend(object):
                 return b.derive_pbkdf2_hmac(
                     algorithm, length, salt, iterations, key_material
                 )
-            except UnsupportedAlgorithm:
+            except UnsupportedHash:
                 pass
-        raise UnsupportedAlgorithm
+        raise UnsupportedHash
 
     def generate_rsa_private_key(self, public_exponent, key_size):
         for b in self._filtered_backends(RSABackend):
diff --git a/cryptography/hazmat/primitives/kdf/pbkdf2.py b/cryptography/hazmat/primitives/kdf/pbkdf2.py
index 71b88211..39427780 100644
--- a/cryptography/hazmat/primitives/kdf/pbkdf2.py
+++ b/cryptography/hazmat/primitives/kdf/pbkdf2.py
@@ -17,7 +17,7 @@ import six
 
 from cryptography import utils
 from cryptography.exceptions import (
-    InvalidKey, UnsupportedAlgorithm, AlreadyFinalized
+    InvalidKey, UnsupportedHash, AlreadyFinalized
 )
 from cryptography.hazmat.primitives import constant_time, interfaces
 
@@ -26,7 +26,7 @@ from cryptography.hazmat.primitives import constant_time, interfaces
 class PBKDF2HMAC(object):
     def __init__(self, algorithm, length, salt, iterations, backend):
         if not backend.pbkdf2_hmac_supported(algorithm):
-            raise UnsupportedAlgorithm(
+            raise UnsupportedHash(
                 "{0} is not supported for PBKDF2 by this backend".format(
                     algorithm.name)
             )