SP2013 Checkif a pdf file is signed through a workflow

Question

Here's a scenario. On SharePoint 2013 in a document library, a user uploads a PDF file with signable fields. Then a workflow kicks off to email another user to go in and review that PDF, and then add his/her digital signature if approved.

Is there a way for that workflow (or another one) to check if a digital signature has been added to the PDF file?

Extra: Is it also possible to check for multiple signatures and verify them specifically with specific fields. For example, there's two signature fields, and the workflow needs to tell which field was signed for two different if/else conditions.

Thanks

Answer 1

You said when user approved the document then signature automatically added to PDF. If this is right then following is helpful.

For verifying one digital signature, you should maintain one extra custom column in SP list like isDigitalSignatureDone (Yes/No). By default this value is NO. When user approved the document then set this field value as YES through workflow/code. Based on this field status, Can find signature is added or not to the PDF.

If you want to know multiple signatures you can add multiple columns or you can add a CHOICE field with multi-select options. You can set value for each signature.

Hope this helps you. If this helps to you, up vote this answer :)

Answer 2

Sort of. You would need to create a custom web service that would check that on the back end and then call that service from the workflow. The amount of effort on the workflow is relatively minimal, but the web service would take some coding effort.