diff --git a/keystone/exception.py b/keystone/exception.py
index bc41bfad3a..42e8cf1759 100644
--- a/keystone/exception.py
+++ b/keystone/exception.py
@@ -578,3 +578,8 @@ class TokenlessAuthConfigError(ValidationError):
 
 class UnsupportedDriverVersion(UnexpectedError):
     debug_message_format = _('%(driver)s is not supported driver version')
+
+
+class CredentialEncryptionError(Exception):
+    message_format = _("An unexpected error prevented the server "
+                       "from accessing encrypted credentials.")