Fingerprint-gui is a package available in the Arch User Repository that provides an interface and drivers for fingerprint readers included on some laptops. The package includes drivers from the open-source project fprint as well as proprietary drivers not included because that particular project has been stagnant for some time.
If you have an older laptop, it is probably wise to try fprint and/or thinkfinger to see if the necessary drivers are included in one of those packages. If your device is still unrecognized and is a Upek device, fingerprint-gui may include the necessary drivers for you device. The package AUR can be installed from the Arch User Repository.
After installation, it is probably wise to make sure your hardware is recognized and correctly working before editing crucial files in pam.d. To do this, launch the setup utility:
$ fingerprint-gui -d
The '-d' is for debugging, and simply creates a verbose log of events. If you are comfortable without the debug info, you may safely omit the flag.
As one would expect from a package with 'gui' in its name, the configuration utility is entirely graphical. Registering your fingerprints is pretty self explanitory as it follows a Windows style "wizard". If a more detailed set of instructions is required, the package includes an install guide in html format.
$ firefox /usr/share/doc/fingerprint-gui/Manual_en.html
Once your fingerprints have been registered, you may notice that in the setup procedure that the "test" section does not yet work. This is because the necessary authentication has not been approved in the appropriate pam.d files.
#%PAM-1.0 auth sufficient pam_fingerprint-gui.so auth required pam_unix.so auth required pam_nologin.so
Keep in mind that your 'sudo' file may contain more entries.
Some users may not have (or want to have) sudo installed on their systems. In this case, it is still possible to use your fingerprint to autheticate su. This can be done just like the sudo example, of course instead adding an entry to /etc/pam.d/su. Again adding the below bold text.
#%PAM-1.0 auth sufficient pam_rootok.so auth sufficient pam_fingerprint-gui.so auth required pam_unix.so account required pam_unix.so session required pam_unix.so
One may also configure such things as GDM, KDM, LightDM and the Gnome-Screensaver. Again, if more information or instruction is needed, please refer to the included manual. The Package Maintainer's Manual might provide further information that cannot be obtained by the included manual.
Now that the necessary authentication has been added to pam, you may wish the confirm the functionality of your setup. The easiest way to do this is to, again, launch the fingerprint-gui. Rather than go through the steps (as your fingerprints should already be established), click directly on the "settings" tab. From here you may select the function you wish to test (ie. sudo, su, gdm, etc).
There is also an included utility to simply confirm that your registered fingerprints are recognized. This can be done by simply running
and following the onscreen instructions.
If you wish to save your user's fingerprint data to a file, simple use the "export" button in the "settings" tab. A file "Fingerprints.tar.gz" will be created in the desired directory. At this time, I have not yet figured out what exactly to do with this saved file though, as I have not come across an "Import" function.
In some cases, using your fingerprint to log into the system may inhibit certain other functions of the desktop environment. For example, Gnome Keyring is dependent on your password, as it is used to encrypt the data in your keyring. To overcome this, fingerprint-gui contains a feature that allows you to store your encrypted password on removable media (USB). You may then use the key to decrypt your keychain by autheticating you rfingerprint while the removable media is plugged in.
The manual indicates that to use this function, mount your USB drive and ensure that you have write access to it. Under the "Password" tab of fingerprint-gui, indicate the appropriate path to your device where it says "Save to directory" (ie. if using gvfs it should be under /run/media/<your uid>/<device>). Enter your password and reenter it and select "save". This will create a hidden directory on your removable media "/.fingerprints" and create a file "<username>@<hostname>.xml". On the local machine, this will also create the file /var/lib/fingerprint-gui/<username>/config.xml.