diff --git a/oletools/ppt_record_parser.py b/oletools/ppt_record_parser.py
index acdc0dd..9deb4c9 100644
--- a/oletools/ppt_record_parser.py
+++ b/oletools/ppt_record_parser.py
@@ -63,7 +63,7 @@ except ImportError:
         sys.path.insert(0, PARENT_DIR)
     del PARENT_DIR
     from oletools import record_base
-from oletools.common.errors import FileIsEncryptedError
+from oletools.common.errors import CryptoErrorBase
 
 
 # types of relevant records (there are much more than listed here)
@@ -181,11 +181,8 @@ def is_ppt(filename):
                         return True
             else:   # ignore other streams/storages since they are optional
                 continue
-    except FileIsEncryptedError:
-        assert ppt_file is not None, \
-            'Encryption error should not be raised from just opening OLE file.'
-        # just rely on stream names, copied from oleid
-        return ppt_file.exists('PowerPoint Document')
+    except CryptoErrorBase:
+        raise
     except Exception:
         pass
     return False