Install gnupg, nautilus integration (seahorse), and restart nautilus
sudo apt install -y gnupg
sudo apt install -y seahorse seahorse-nautilus
killall nautilus
Import Keys
Configuration files can include sensitive information such as passwords, contact information, or other personal information you don’t wish to share, even though you may wish to store it in the cloud for easy retrieval. In that case it’s a good idea to encrypt those files with a personal key. Here is how you load your previously generated key so you can unencrypt them.
gpg --import "my/remote/filesystem/keys/file.asc"
See GPG Reference