OK. So, by AD ID you mean your Windows user password, right? What does it have to do with authenticating PDFs? When you say "authenticate PDF". do you mean restricted opening of a PDF (encryption) or proving that it has not been changed (signing). In the latter case what kind of signature do you have in mind: digital signature (with a certificate) or eSignature (EchoSign)?
The only scenario that makes sense to me is that you want to encrypt PDF in such a way that only people with certain user IDs can open it. Is this correct? This is encryption, not signing. And encryption does not have timestamps.
If you elaborate on the workflow you want to achieve providing as many details as you can, then we can advise you. So far I do not understand what you're trying to accomplish.