Signed Script Policy-3
The associated principal allows the user to confirm the validity of the certificate used to sign the script. The user can ensure that the script hasn't been tampered with since it was signed. The user may grant privileges based on the validated identity of the certificate owner and validated integrity of the script.
An simpler alternative to using the Page Signer tool to sign scripts is to serve them from a secure server. On the browser, scripts act as though they were signed with the public key of that server. There is no need to sign the individual scripts.
SSL servers are particularly helpful if scripts are dynamically generated on the server side.