[ale] Deal on yubikey HW for 2FA

[DJ-Pfulio]

Hope that nobody minds this ...

Github and Yubico are pushing 2-Factor Authentication by making it VERY
cheap.  $5 for a device + shipping and handling.  Limit 2; having 2 is a
"best practice" to avoid issue if you loose one when traveling.

The offer:
https://www.yubico.com/github-special-offer/github-yubikey-special-offer/

-------
I ordered 2 - total cost was $15 including shipping.

An unvalidated list of websites claiming support for the U2F protocol:
  http://www.dongleauth.info/

Only downside that I know is Google Chrome or Chromium browsers are
required. Doesn't work with Firefox. There appears to be some udev setup
required as well.

Anyway - cheap protection against phishing  and replay attacks for some
online websites.