Reports of a biometric sensor in the upcoming iPhone 5S have been floating around for some time. However, with the release of iOS 7 beta 4 to developers 9to5Mac has posted new evidence that the fingerprint scanner is real. The code reveals a folder named "BiometricKitUI.axbundle" featuring the building blocks to run a biometric sensor.
According to sources, Apple has completed work on the user interface for such a feature, which would presumably unlock the device. Instead of typing a passcode, all that would be needed for a home button fingerprint scan is to press the button. The leaked strings indicate that during the setup process, a fingerprint graphic would change color when registered.
The VoiceOver tutorial describes a user holding the iPhone with one hand, while pressing the home button with a thumb to unlock:
Photo of a person holding an iPhone with their left hand while touching the Home button with their thumb
Photo of a person holding an iPhone with their right hand while touching the Home button with their thumb
A fingerprint that changes colour during the setup process.
Recognition is %@ complete