Apple is reportedly using a fingerprint scanner in a future iPhone model to increase the security of NFC (near-field communication) payments.
Some rumors suggest that this will be integrated into the iPhone 5S, but it’s not clear if that’s the case, and it seems that Apple would wait since the S-models of past handsets are typically the same body with some internal and software upgrades.
That said, Apple did acquire AuthenTec a while back. This seemed like a move to increase security on its devices in some way. No specifics were mentioned, and Apple didn’t discuss details. While it’s possible that the iPhone 5S will integrate this technology, it seems more like an iPhone 6 thing. That’s when I imagine Apple will update the design in a more significant way.