Frederik ElwertSince our university ditched both Adobe and Master PDF, and the new PDF solution is not available for #Ubuntu #Linux, I was looking for a viable PDF signing solution. It appears that the new #GNOMEPapers app actually supports this! With caveats … 1/
The first issue was getting Papers to find my certificates. After digging in the Poppler source code, I found that they hard-code the path they check as '$HOME/.mozilla/firefox'. But Ubuntu ships the #snap version of Firefox, which uses '$HOME/snap/firefox/common'. Could solve this by soft linking the snap profile dir to the expected one. (Just copying cert9.db and key4.db also worked.) Now I can sign! 2/
But Papers itself shows a warning that the signature is not valid. Still have to find out why. It doesn’t tell much, unfortunately. Using other checkers, it might be that it either cannot establish the certificate path (unknown root cert), and/or that the 'signing-time' property is missing. 3/3
fmbdx@felwert Apparently, Firefox can do that now.
From https://www.omgubuntu.co.uk/2025/04/firefox-137-new-features
From https://www.omgubuntu.co.uk/2025/04/firefox-137-new-features
@fmbdx Thanks! I think that only means adding a hand-written signature, not an actual certificate-based signature, though? (The terminology in this space it utterly confusing …)
@felwert I just seen that :
https://tugaleres.com/2025/04/07/stirling-pdf-le-couteau-suisse-pour-gerer-vos-fichiers-pdf-via-navigateur/
Looks nice. Free, locally-installable and I can see a "sign with certificate" function on the screenshot.
Article is in french, but browser translator should do.
https://tugaleres.com/2025/04/07/stirling-pdf-le-couteau-suisse-pour-gerer-vos-fichiers-pdf-via-navigateur/
Looks nice. Free, locally-installable and I can see a "sign with certificate" function on the screenshot.
Article is in french, but browser translator should do.
@fmbdx Merci! I had seen it before, but I didn't think of it in the context of document signing. Will give it a shot!
Alexander Winkler@felwert just out of curiosity: The Okular solution ist not viable (https://www.luis.uni-hannover.de/de/services/it-sicherheit/zertifikate-der-luh-ca/anleitungen/okular-pdf-signatur-unter-linux)? It's stunning that in 2025, after an epidemic that entailed remote work for large parts of administration and academia, such apparently easy things are still so hard ...
@awinkler It might be, I’m just a bit hesitant to pull in half of KDE just to sign a document. But it’s probably the most stable solution, you’re right. And then this year our university actually started its own online signing service. IANASR (I am not a security researcher), I just find it weird that the service uses a single, university-wide signing key, while we can all get our personal certificates.