The magic behind Apple's Touch ID technology has received an unveiling in the form of the company's latest pair of patent applications. One of the patents describes the various parts of the button itself and how it senses and reads a finger touching it. The other patent discusses how the fingerprint data and verification are kept separate from the rest of the system.
The button structure may be familiar with those who have seen some of Apple's marketing images of the button, its parts telescoped for easy visualization of how it is assembled. The assembly in the patent is shown from the bottom up, including the casings, rings, sensor circuit and scanning lens. The opaque covering for the button lets the finger be scanned while blending with the iPhone's color and styling.
The fingerprint verification system uses a "Secure Enclave Processor" (SEP) within the A7 chip. This keeps the data separate from apps and the cloud. The A7 chip does the heavy processing and hands off a pared-down set of data about the fingerprint to the SEP, which can then verify the fingerprint.
Much of the information revealed in the patents was already known, but the patents confirm some of the nuts and bolts in the design, especially those concerning the SEP. Although not yet granted, the patents follow up provisional applications filed early last year and will secure Apple's claim on the technologies.