PDFBox - opening and saving a signed pdf invalidates my signature

Question

I am trying to learn to use Apache\'s pdfBox to deal with digitaly signed documents for work. During testing, I created a completely empty pdf document.

I then signe

Answer 1

From what I can gather from some of Adobe's documentation, there is a timestamp which is included as part of the signature. I would guess by saving the document (even without any content changes) would modify this timestamp value, hence invalidating the signature (which would have been created using the original timestamp).

This isn't an authoritative, mind you - this is just what I've been able glean from a quick glance at Adobe's documentation on the matter.