Notebooks can also use a security digest to ensure the correct user is modifying the contents. A digest takes into account the entire contents of the Notebook and a secret (only known by the Notebook creator). This combination ensures that malicious coding is not going to be added to a Notebook.

You can add a security digest to a Notebook by using the following command:

~/.jupyter/profile_default/security/notebook_secret 

Here, you replace the notebook_secret part with your secret.