Using a U2F key instead of a password on Linux

This is an update and expansion on something I wrote a few years ago about using my SoloKey U2F USB key for passwordless sudo. Recently, I ended up typing my password into a Slack window while trying to unlock my computer. By the time I’d realised that it wasn’t locked but had merely blanked the screen, my muscle memory was far ahead of my brain. As I went through the hassle of updating my password and brain, I couldn’t help wondering whether there was a better way. The solution I’ve found lets me unlock my computer with a short PIN and my U2F key, and to use just the key for sudo. These instructions are for Debian with Gnome; they will probably work on Ubuntu, and for other distributions and desktop environments you might have to make some changes. Setting up the SoloKey First, you need to set the PIN on your U2F key. I have an original SoloKey (two of them, in fact), so I need to use the solo1 command. This is afflicted by bitrot, but if you have Python installed you can work around…