A pair of patent applications related to Apple's new flagship iPhone feature Touch ID shed some new light on how the fingerprint sensor itself works, as well as the "Secure Enclave" inside the A7 processor that analyzes and stores user fingerprints. The first, as noticed by Patently Apple, details a method by which the iPhone scans a finger and then provides that data to the "Secure Enclave" for matching and eventual approval. Rather than storing actual images of fingerprints, Apple takes a fingerprint map and runs it through a sort of encryption to prevent thieves from pulling fingerprint data from a compromised iPhone. The enclave only allows fingerprints to be checked against known valid ones, not the other way around.
