Print restrictions and Signatures

Ok, I didn't see the last bit of your last response. So ignore my first answer. 

You are already using Adobe Sign.The final PDF returned after signing is "Signed" with a a digital certificate, which prevents further edits to the PDF.  As you've discovered, the password security needs to be added before the the digital certificate is applied.  Did you try adding the password to the PDF itself  before putting it into the Adobe Sign process?

It depends on your angle and what other surprising elements  are you willing to share about the current workflow in your organization.

Not sure if you actually posted a statement or an actual question.

But you don't have them sign and then add security and restrictions. You first create the PDF document, then you add restrictions and protect with password, then you send for signature.

Here's the apropriate Adobe guidance: 

• https://helpx.adobe.com/reader/using/print-pdfs.html#why_can_t_i_print_my_document

And here's the appropriate workflow if what you're actually asking about concerns about enforcing security standards in your workflow:

•   https://helpx.adobe.com/reader/using/send-for-signature.html

Is this simple enough or shall I elaborate more???