On 2018-06-05 15:54, Andrei Borzenkov wrote:
On Tue, Jun 5, 2018 at 4:39 PM, Carlos E. R. <robin.listas@telefonica.net> wrote:
On 2018-06-05 15:31, Andrei Borzenkov wrote:
On Tue, Jun 5, 2018 at 4:14 PM, Carlos E. R. <> wrote:
I talk about signing with an official certificate, not stamping the document with an image. And when displaying such a signed document, display the certificate authenticity trail. Nothing in Linux, AFAIK, does that - except proprietary acroread, and it is ancient, so it can not update its master certificates.
There is at least one free (IANAL) toolchain for manipulating PDF (iText) and at least one standalone program using it for document signing (jPdfSign). So if you really need it, you may consider this route.
Thank you.
Libre Office can sign the PDF it generates, so there must be free and open methods of doing it.
But still I know no method to verify the signatures in Linux. That's what I need. Maybe there is a CLI method separate from readers.
I would expect that toolkit that supports signing also supports verification.
Maybe. Difficult to say reading here: <http://jsignpdf.sourceforge.net/> I googled for "validate digital signature for PDFs in linux", and two places say to try "PDF Studio Viewer". There is also a comment or two that say Evince is going to get signature support via poppler. Here is some info on Evince: <https://askubuntu.com/questions/226257/how-can-i-validate-a-pdfs-digital-signature-with-evince> I will try this: <https://www.qoppa.com/pdfstudioviewer/> There is a reader gratis version. [...] Ok, downloaded and installed on a 15.0 Vbox VM. It is a java program, comes with its own JRE. It feels slow. VB is slower than Vmware in my machine. It does display signature info :-) Similar to acroread, but with less info, it seems, but more than "pdfsig" (see my other email). Ah, on each field I can right click and select "details", and this info is indeed detailed. Next is to find how to add "Trusted identities". Found it, in preferences I can import root certificates. I must try this out, but has to be another time. It also appears to load forms correctly. :-) Finally, it can also take photos of the document (PNG file or clipboard). Very good PDF reader! :-) -- Cheers / Saludos, Carlos E. R. (from 42.3 x86_64 "Malachite" at Telcontar)