Square & VeriFone, My phone accepts payment cards

Square allows you to turn your phone into a payment card terminal.

Cool. For a mere 2.75% overhead, a merchant can accept credit cards using a free magnetic card reader attached to your phone headset jack. Your customers swipe their card and scribble their signature on your iSplat’s screen, your bank account gets a credit.

The obvious questions: How do you secure a mobile application such that it can safely handle payments? Is your Square enabled phone now covered under some sort of compliance regime?

Temporal Juxtaposition - The future of mobile banking

E-mail from a colleague:
So, within minutes of one another: 
Roundtable's Pitts: Mobile Will Connect Channels, Improve Security
"Mobile and banking fit together like chocolate and peanut butter," says Jim Pitts, project manager of the Financial Services Technology Consortium, the technology solutions division within The Financial Services Roundtable.
[ ... ] 
Google Kicks Rogue Apps Out of the Android Market
"[ ... ] Before their removal, the apps garnered between 50,000 and 200,000 downloads. The apps caused the phone to perform functions without the owner's consent. The Trojan embedded in them used a root exploit to access all of the phone's data and download malicious code. 
The publisher has been removed from the Android Market completely, and its apps reportedly have been deleted from phones, but this won't remove code that has been back-doored into a phone's program. Google reportedly is working on that problem.
[ ... ]

Awesome. We are going to bet our financial future on a rootable platform. I wonder how that will turn out.

I’m feeling déjà vu.