This guide covers how to secure a local Linux login using the U2F feature on YubiKeys and Security Keys. This does not work with remote logins via SSH or other methods. The commands in the guide are for an Ubuntu (or Ubuntu based) system, but the instructions can be adapted for any distribution of Linux.
Securing your Linux server is important to protect your data, intellectual property, and time, from the hands of crackers (hackers). The system administrator is responsible for security of the Linux box.