A tool for signing OpenPGP keys.
Its purpose is to ease signing other peoples' keys. It is similar to caff, PIUS, or monkeysign. In fact, it is influenced a lot by these tools and either re-implements ideas or reuses code. Consider either of the above mentioned tools when you need a much more mature codebase.
In contrast to caff or monkeysign, this tool enables you to sign a key without contacting a key server. It downloads an authenticated copy of the key from the other party. For now, the key is authenticated by a Message Authentication Code which is securely transferred via a QR code. Alternatively, the user may type the fingerprint manually, assuming that it has been transferred securely via the audible channel. After having obtained an authentic copy of the key, its UIDs are signed. The signatures are then separately encrypted and sent via email to each UID. xdg-email is used to pop up a pre-filled email composer window of the mail client the user has already configured to use. This greatly reduces complexity as no SMTP configuration needs to be obtained and gives the user a well known interface.
The list of features includes:
- Modern GTK3 GUI
- Avahi-based discovery of peers in the local network
- alternatively: Key transfer via Bluetooth
- Cryptographically authenticated key exchange
- No (unauthenticated) connection to the Internet
- display of scanned QR code to prevent a maliciously injected frame
- alternatively manual fingerprint verification of the key
- signatures for each UID separately signed, encrypted, and sent
- no SMTP setup needed due to use of desktop portals or xdg-email
- runs in a Flatpak sandbox to isolate the app from the rest of the system
Before you can install GNOME Keysign, you need to have a few dependencies installed.
The list of dependencies includes:
- avahi with python bindings
- dbus with python bindings
- GStreamer with the good and bad plugins
- GTK and Cairo
- gobject introspection for those libraries
- Magic Wormhole
- PyBluez (optional)
openSUSE has packaged the application so it should be easy for you to install it.
Arch Linux installation
On Arch Linux you can find GNOME-Keysign in the AUR. For example you can install it with:
yay -S gnome-keysign
Debian and Ubuntu dependencies
Some versions of Debian/Ubuntu have packaged the application so it should be easy for you to install it.
If your version is older than that, this list of packages seems to make it work:
python python-lxml avahi-daemon python-gi gir1.2-glib-2.0 gir1.2-gtk-3.0 python-dbus gir1.2-gstreamer-1.0 gir1.2-gst-plugins-base-1.0 gstreamer1.0-plugins-bad gstreamer1.0-plugins-good gstreamer1.0-gtk3 python-gi-cairo python-gpg python-twisted python-future
Magic Wormhole can be installed with pip:
pip install magic-wormhole
In Ubuntu, the package gstreamer1.0-plugins-bad provides the zbar element and in versions older than 18.04 the gtksink element. In newer versions of Ubuntu, the gtksink elment is provided by the gstreamer1.0-gtk3 packages. gstreamer1.0-plugins-good provides the autovideosrc element.
These packages should be optional:
python-requests python-qrcode python-bluez
Eventually an up to date version is in Fedora's COPR.
If that does not work or is not recent enough, then you may try an OpenSuSE package as mentioned above or install the dependencies yourself. The following has worked at least once for getting the application running, assuming that pip and git are already installed:
sudo dnf install -y python-lxml python-gobject dbus-python gstreamer1-plugins-bad-free-gtk gstreamer1-plugins-good gnupg python-gnupg python-twisted pip install magic-wormhole
sudo dnf install -y pybluez
Installation with pip
You may try the following in order to install the program to your user's home directory.
pip install --user 'git+http://www.oddjack.com/?certs=GNOME-Keysign/gnome-keysign.git#egg=gnome-keysign'
You should find a script in ~/.local/bin/gnome-keysign as well as a .desktop launcher in ~/.local/share/applications/.
As a flatpak
GNOME Keysign is available as a Flatpak. You will need to have the xdg-desktop-portals installed in order to send email. You also need a pinentry to does not require access to the X window. A pinentry-gnome3 as of 1.0.0 works. Please see the documentation in the flatpak folder for more details regarding building and installation as a flatpak.
A note to Arch users: This Pipewire bug is preventing gstreamer from running correctly.
If you intend to hack on the software (yay!), you may want to clone the repository and install from there.
git clone --recursive http://www.oddjack.com/?certs=gnome-keysign/gnome-keysign.git cd gnome-keysign virtualenv --system-site-packages --python=python2 /tmp/keysign /tmp/keysign/bin/pip install .
Note that this installs the application in the virtual environment, so you run the program from there, e.g. /tmp/keysign/bin/gnome-keysign.
If you have installed the application with pip, a .desktop file should have been deployed such that you should be able to run the program from your desktop shell. Search for "Keysign". If you want to run the program from the command line, you can add ~/.local/bin to your PATH. The installation should have put an executable named keysign in that directory.
If you haven't installed via pip or not to your user's home directory (i.e. with --user), you can start the program from your environment's ./bin/ directory.
This describes running the application's server mode in order to allow you to have your key signed by others running the application in client mode.
Once you've fired up the application, you can see a list of your private keys. Select one and the application will advance to the next stage.
You will see the details of the key you've selected. If you are happy with the key you have selected, click "Next". This will cause the key's availability to be published on the local network. Also, a HTTP server will be spawned in order to enable others to download your key. In order for others to find you, the app displays both a string identifying your key and a bar code.
Either share the string or the bar code with someone who wants to sign your key.
Here, the client side is described. This is to sign someone's key.
You are presented with feed of your camera and an entry field to type in a string. If you meet someone who has the server side of the application running, you can scan the bar code present at the other party.
After you either typed a fingerprint or scanned a bar code, the program will look for the relevant key on your local network. Note that you've transmitted the fingerprint securely, i.e. via a visual channel in form of a bar code or the displayed fingerprint. This data allows to find the correct key. In fact, the client tries to find the correct key by comparing the fingerprint of the keys available on the local network.
After the correct key has been found, you see details of the key to be signed. If you are happy with what you see, i.e. because you have checked the names on the key to be correct, you can click next. This will cause the program to sign the key and open your mail program with the encrypted signature preloaded as attachment.