Can't clear signatures to update docs with minor changes

[VinceS]

Hi, just made the transition from Acrobat X1 to PDF-Xchange Pro and find an ability I have long relied on to recycle docs for annual returns or other recurrent purposes is not available in PDF-XC. Or to fix simple mistakes after the doc was issued, we call this a revision! But, try to clear my signature, and get:

image.png

This is serious trap and a significant defect in expected use of the software, which I now see in these forums people were complaining about 10 years ago, then went quiet so presumably fixed, but alas, seemingly not. Had I been aware of this impediment, I would have kept the unsigned copies, but now I have a whole bunch of docs that I thought were done with but have been asked to update a four of them by my Accountant and this seems to be impossible. Others will need to become donor docs in a year. Or completely regenerate them, which is not something Acrobat ever made me do.

All I did, in PDF-XC, was to create a new signature, which I just use an image for and un-tick everything else. I was surprised at the lack of a p/w to apply it, but not really concerned about that. So I sign and save it, delete the unsigned one and, unfortunately, have emptied my recycle bin in the interim so it is forensic retrieval, if that is possible.

How do I get to clear my own signatures and recycle / update docs as I see fit? Thank you.

Edit: Forensic recovery didn't work, so I must have saved the signed copies over the unsigned ones. I also tried opening them on another PC still with Acrobat and there was no clear signature option, guess security has moved on a bit.

[Daniel - PDF-XChange]

Hello, VinceS

Signatures can only be removed by a device which has the original certificate file that was used to place it (with all placement criteria, such as the internal "private key" data), on hand.
Historically this was limited to certificates located in the windows "certificate store" however, with 10.7 we now offer a certificate management area, and if you have external signature files (in *.pfx or *.p12 format) you can "attach" those to the Editor, and we can now use them to remove certificates from the file as well.

• Note that this is an intended security feature of digitally signing in PDF. It should be expected from any reputable PDF handler, to respect the security of the original signers certificates. This ensures the security that is put in place during a signing action, as dictated by the PDF Specification, is not flagrantly disobeyed.

In your case, you will need to ensure that you have the certificates which were used to place that signature locally on your device. If these are windows "system store" certificates, you will likely need to export them from an old device, and import them on the new one using Windows' certificate manager:

image.png

Once you have done that, you should be good to go.

If instead you have a *.pfx file floating around on your desktop somewhere, like I do:

image(1).png

You can use the "manage" menu to attach these files to your Editor installation, which should in turn allow you to remove the corresponding certificates from your documents.

image(2).png

Kind regards,

[VinceS]

Thank you for going to the trouble to make that explanation, I learnt a bunch of stuff about how Windows handles certificates and tried to find a way, but ultimately no material improvement. Only looking in Personal certs out of everything there; could see expired certs and the two new ones I had made in the interim, but no sign of the credentials needed on main PC, spare which is a clone (now with a new SID after a recent MS update that wrecked networking of clones!), or laptop. So I regenerated these docs from scratch, kept the unsigned copy and now note if don't say No Changes, can clear signature anyway. So, now I know.

Also, by way of erratum, a No Changes Acrobat X1 doc can't have its signature cleared either, completely contrary to my beliefs on the topic, but the evidence was there and I am an evidence guy, despite the belief suspension problem. I absolutely have, many times, cleared such sigs. I note Acrobat still updates digital signatures of some kind, maybe that moved something from possible to nope. Anyway, got my feet in the modern era, now just have to sort out the next irksome problem (after search and possible new topic, no preview needed)

[Dimitar - PDF-XChange]