Using Yubikeys at Princeton
Since 2016, Princeton has been using Duo for 2-factor authentication (2FA). Most users interact with Duo by way of the Duo Mobile application on a smartphone.
Duo
SSH: Duo Two-Factor Authentication (2FA)
This page is an extension of CS Guide's Secure Shell (SSH).
Duo 2FA is required for all SSH logins to Princeton University Computer Science research & computing servers. These include cycles.cs.princeton.edu (aka portal, soak/wash/rinse/spin), ionic.cs.princeton.edu, courselab.cs.princeton.edu, and armlab.cs.princeton.edu.