There is no requirement to have had a hardware authenticator prior to using the mobile authenticator app. Think about it this way... the software is free, you're paying for the hardware, by either paying $7 for the keyfob, or $300 for the iPhone.

Casinos? Wow, that brings me back...

@BillDoor

I was under the impression you needed the serial number from the authenticator to activate the program on the iPhone. I believe it was in the article about it on this site.

So yes, you do need a physical authenticator. It's not like Google makes profit from the $300 iPhone.

Oh wow, I think I'm actually wrong about this.

https://us.battle.net/account/support/mobile-authenticator.xml?rhtml=y

You do not need a hardware (the $6 one) authenticator to use the iPhone one. The iPhone app starts up and shows you a serial number that you enter on the website to initialise it. It's randomly generated, and you can reset it UNTIL you enter it on the website. After that, if you uninstall the app, reset the serial number or have to reset your phone and lose the app for any reason you'll be on the phone with Blizz.

What is so special about the iPhone? Why can't we have a PC-based authenticator?

@Schadow

I think the point is, its a seperate unit. Not much point having an authenticator on your PC if your PC is riddled with key loggers, The key loggers would have access to the autenticator software...

See the problem there? besides i think they are intending to add support to other devices, but given the popularity of the iPhone, and the fact its a stable bit of hardware (not a variety of different phones it could potentially run on if it were say Java based) Its probably a good testbed to run the app on.