Document Encryption

Document encryption before email workflow.

I have a customer request to send an Acumatica generated document, in this case a PDF, as encrypted to secure the document so that it can only be opened by the recipient who would know the password for the document. This would be part of workflow and they would not want to download the document from Acumatica to their local computer, encrypt and then send the email.
I have searched for such a plugin and have not found anything. Has anyone performed such a request before and what did you use. Or is there not a solution for this and it would require a customization to use an encryption routine?

Any guidance or direction is appreciated. Thank you.