How To Use OPIE to Get One-Time Passwords for FreeBSD 10.1
In this tutorial, you will learn how to generate and use one-time passwords to log in to your remote FreeBSD server. You can pregenerate one or more one-time passwords when you’re in a safe location, and save them for later when you access your server from a less secure location. That way, even if your one-time password gets logged, it won’t ever be useful to an attacker.