I have the same problem, too. Installing gimp I came up with the following errors:
error: libglade: signature from “Luca Giambonini XXX@XXXXX” is unknown trust
:: File /var/cache/pacman/pkg/libglade-2.6.4-4-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
error: pygtk: signature from “Luca Giambonini XXX@XXXXX” is unknown trust
:: File /var/cache/pacman/pkg/pygtk-2.24.0-3-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
following the post I launched the following commands to try to solve the problem by running the following commands:
$ sudo rm -r /etc/pacman.d/gnupg #remove all the keys installed in my system
re-add the default keys
$ sudo pacman-key --init # followed
$ sudo pacman-key --populate chakra
$ sudo pacman-key --refresh-keys
$ sudo pacman -Syu
The problem mentioned above remains. How can I fix and install gimp correctly?