iOS 7 beta 4 was just released, and it looks like Apple has been tinkering with a few more ideas that could change the way we use the next edition of the iPhone.
Developer Hamza Sood discovered code hidden within iOS 7 beta 4 that indicates that Apple's bringing a fingerprint sensor to the operating system. The code references a biometric sensor that would be placed in a future version of the iPhone's home button. Sood found the code under a folder labelled BiometricKitUI, which you can see here. Technology like this could be useful for privacy protection, and may end up replacing the number-based code that Apple has used for iPhone and iPad security since their original release.
There have been rumors that Apple may be upgrading their Passbook service and releasing an Apple payment system, and fingerprint identification would add an extra layer of protection to those sensitive services. With all beta rumors and discoveries, this hasn't been made official for the final version of iOS 7 in the fall—but this one seems likely, especially because it makes sense down the line.