diff --git a/IPython/html/services/contents/manager.py b/IPython/html/services/contents/manager.py
index 10eeda56e..f8170bea5 100644
--- a/IPython/html/services/contents/manager.py
+++ b/IPython/html/services/contents/manager.py
@@ -498,7 +498,6 @@ class ContentsManager(LoggingConfigurable):
         """Create a checkpoint."""
 
         nb = nbformat.from_dict(self.get(path, content=True)['content'])
-        self.check_and_sign(nb, path)
         return self.checkpoint_manager.create_checkpoint(nb, path)
 
     def list_checkpoints(self, path):
@@ -513,8 +512,6 @@ class ContentsManager(LoggingConfigurable):
             path,
         )
 
-        self.mark_trusted_cells(nb, path)
-
         model = {
             'content': nb,
             'type': 'notebook',