GCR is a library for displaying certificates and crypto UI, accessing key stores. It also provides the viewer for crypto files on the GNOME desktop.

GCK is a library for accessing PKCS#11 modules like smart cards, in a (G)object oriented way.

You can build GCR using Meson with the following build commands (replace $BUILDDIR with your chosed build directory).

$ meson setup $BUILDDIR
$ meson compile -C $BUILDDIR
$ meson install -C $BUILDDIR

The code and issue tracker of GCR can be found at the GNOME GitLab instance at https://gitlab.gnome.org/GNOME/gcr.

If you would like to get involved with GNOME projects, please also visit our Newcomers page on the Wiki.

The documentation for GCR and GCK is built using gi-docgen.

You can find the nightly documentation at:

• Gck: https://gnome.pages.gitlab.gnome.org/gcr/gck-2/
• Gcr: https://gnome.pages.gitlab.gnome.org/gcr/gcr-4/

You can find the older GCR documentation at:

• Gck: https://gnome.pages.gitlab.gnome.org/gcr/gck-1/
• Gcr: https://gnome.pages.gitlab.gnome.org/gcr/gcr-3/
• GcrUI: https://gnome.pages.gitlab.gnome.org/gcr/gcr-ui-3/

The Gcr and Gck libraries contain statements which help debug flow and logic. In many cases these help you track down problems.

Use the environment variable G_MESSAGES_DEBUG='all' or G_MESSAGES_DEBUG='xxx' to display either all messages or a specific categories of debug messages. You can separate categories in this list with spaces, commas or semicolons. Gcr library uses category 'Gcr', while Gck library uses category 'Gck'.

# Example to display all debug messages:
$ G_MESSAGES_DEBUG=all gcr-viewer /path/to/certificate.crt

# Example to display debug messages for a specific category:
$ G_MESSAGES_DEBUG="Gcr" gcr-viewer /path/to/certificate.crt

For the Gck debug messages simply replace 'Gcr' with 'Gck' in the above examples.

To discuss issues with developers and other users, you can post to the GNOME Discourse instance.