ARM is presenting this hardware based secure payments and authentication system which all future mobile devices may be shipping with. The functionalities of those calculators that people use for their netbanking can thus be integrated in the future mobile phones, to let people do secure payments and authentication using a simple 4 number pin code on their mobile phone. The way they do it is that they guide the keyboard entries directly into a separate secure encrypted OS that functions separately from Android to do the secure authentication that then sends back the certificate (or how it's called) back to the web based application. This kind of system, I would guess, could also be integrated in laptops, or you could use your phone to authenticate yourself on any website very securely using any computer.
You can find more information about this at: http://www.arm.com/markets/mobile/trustzone-and-mobile-payments.php