You don't need a Google account... just the Google Authenticator software, and the secret key that ArenaNet gives you on their pages for enabling mobile authentication.
Google Authenticator is available as apps for many smartphones - you can download them from the same ArenaNet web pages during mobile authentication setup.
If you don't have a smartphone, you can use a Windows application instead - gauth4win... but be aware, gauth4win stores your secret key in plain text in the Windows registry of the PC that you use gauth4win on. Not ideal.
You can also use a $25 YubiKey (USB key), via YubiKey's Windows helper application. With this, your secret key only exists on the USB key (and at ArenaNet, obviously). This is what I am using.
BTW, Mobile Authentication is NOT 2-factor authentication as advertised - it does not prompt you to authenticate if you login from a "remembered network" - and it's the same remembered networks as email authentication. ie. if you are already using email authentication, you won't ever see the mobile authentication prompt unless you login from a different geographic location and/or ISP.
So, as it is:
-We can’t tell if it’s in place and working or not, except by logging in from a different network
-It assumes your PC (and everyone using the same ISP in your general area) can never be infected by remote access/control malware
-It assumes nobody on the same network as you, will ever try to rob your account
-It assumes Mr Account Thief can never spoof your address
-It assumes your PC can never be physically accessed by other people in your building/campus/whatever
It's all a bit rubbish, until we are able to delete remembered networks. There is currently no way to do that, but apparently they are planning to allow it. Hopefully that will let us have NO remembered networks, so we have the choice to always get the mobile authentication prompt (if we want it).
Edited by Righteous, 05 December 2012 - 05:41 PM.