certificate manager

I am trying to sign letters with digital signature, when I open File>Digital Signatures> Digital Signature I get an empty Digital Signature window and when I click the Start Certificate Manager… I get an error window saying “Could not find any certificate manager.” Where is the Certificate Manager? What should I do?

Sorry for not giving my OS: I use Ubuntu20.04.2LTS
Gnome 3

Many thanks for the help.

Addition. Yes I have gnupg and a key but how am I going to put it in certificate manager?

Sorry for bothering you, but I installed kgpg and nothing happened. Still when I want to sign a LO writer doc I get empty digital signatures window and certificate manager can not be found.

Managing X.509 certificates and others is an OS matter. Edit your question to mention your OS (and LO version as implementation may vary).

Once you’ve created your certificates with whatever utility your OS provides (e.g. Kgpg on my Linux KDE-deskptop box), this becomes a LO interface question. But beforehand, this is an OS question.

Please do not use Add Answer but edit your original question to enhance the details of your question (answers are reserved for solutions to a problem on this Q&A site).

And which desktop? Unity? GNOME, KDE?

Have you installed openSSL? Certificates depend on this utility and its library. Over it, you have GUI like Kgpg (for KDE). Look for packages related to GnuPG with your package manager.

I am under Fedora 34 with KDE Plasma desktop. Intalled packages related to GPG are gpgme (GnuPG Made Easy) and kgpg (GUI to manage GPG keys). I guess kgpg is considered the certificate manager because LO launches it when I press the button. I have no idea of the equivalent package for GNOME.

I installed kgpg and nothing happened

There may be 2 reasons: the “k” in kgpg tells it is intended for KDE (not GNOME) and (2nd reason) “primary” packages may be missing.

Since I make my own certificates for my server, I have also installed openssl. But this is not really a “certificate manager”, it is the certificate factory.

As I said, I am under KDE and have no idea about what is needed under GNOME. I rely on automatic dependency resolution by the package manager. So, I tell which end-product I want and leave library installation to the package manager.

I read in a website and removed LO snap and installed LO from its website and had no problem in using digital signature. There seems to be some bug in snap version.

@okkadiroglu: I reopened and closed your question, changing the reason. “Duplicate” was not the good choice. I changed it for “Answered” though this doesn’t seem to me optimal choice.