Switch to using our own InternalError, instead of SystemError

3 files changed, 14 insertions, 5 deletions

diff --git a/cryptography/exceptions.py b/cryptography/exceptions.py
index 44363c24..2654b453 100644
--- a/cryptography/exceptions.py
+++ b/cryptography/exceptions.py
@@ -34,3 +34,7 @@ class InvalidTag(Exception):
 
 class InvalidSignature(Exception):
     pass
+
+
+class InternalError(Exception):
+    pass
diff --git a/cryptography/hazmat/backends/commoncrypto/backend.py b/cryptography/hazmat/backends/commoncrypto/backend.py
index 7193f1d8..ebb834cb 100644
--- a/cryptography/hazmat/backends/commoncrypto/backend.py
+++ b/cryptography/hazmat/backends/commoncrypto/backend.py
@@ -16,7 +16,9 @@ from __future__ import absolute_import, division, print_function
 from collections import namedtuple
 
 from cryptography import utils
-from cryptography.exceptions import UnsupportedAlgorithm, InvalidTag
+from cryptography.exceptions import (
+    UnsupportedAlgorithm, InvalidTag, InternalError
+)
 from cryptography.hazmat.backends.interfaces import (
     HashBackend, HMACBackend, CipherBackend
 )
@@ -197,8 +199,9 @@ class Backend(object):
                 "the block length"
             )
         else:
-            raise SystemError(
-                "The backend returned an error. Code: {0}".format(response)
+            raise InternalError(
+                "The backend returned an unkown error, consider filing a bug. "
+                "Code: {0}.".format(response)
             )
 
 
diff --git a/cryptography/hazmat/backends/openssl/backend.py b/cryptography/hazmat/backends/openssl/backend.py
index ee82ba71..b5116be4 100644
--- a/cryptography/hazmat/backends/openssl/backend.py
+++ b/cryptography/hazmat/backends/openssl/backend.py
@@ -16,7 +16,9 @@ from __future__ import absolute_import, division, print_function
 import itertools
 
 from cryptography import utils
-from cryptography.exceptions import UnsupportedAlgorithm, InvalidTag
+from cryptography.exceptions import (
+    UnsupportedAlgorithm, InvalidTag, InternalError
+)
 from cryptography.hazmat.backends.interfaces import (
     CipherBackend, HashBackend, HMACBackend
 )
@@ -154,7 +156,7 @@ class Backend(object):
                         "the block length"
                     )
 
-        raise SystemError(
+        raise InternalError(
             "Unknown error code from OpenSSL, you should probably file a bug."
         )