iPhone Touch ID

When Apple first revealed the Touch ID system, the company described a "secure enclave" within the A7 chip which stores sensitive fingerprint data. Now thanks to two patent applications detailed by Patently Apple, the mechanics of this secure enclave have been explained.

Images of fingerprints are never stored in the secure enclave or elsewhere. Fingerprint map input from the Touch ID sensor is processed and stored using a kind of encryption. For security when unlocking the iPhone, MacRumors explains that "the enclave only allows fingerprints to be checked against known valid ones, not the other way around."

The days of swapping out a broken home button in a do-it-yourself (DIY) iPhone repair are over. Now that the iPhone 5s features Touch ID, iMore points out new hardware security features that could mean more trips to the Genius Bar. This is a side effect of protecting fingerprint data by locking down the Touch ID components.

The image above from iFixit shows the fingerprint sensor and component cable assembly, which are uniquely linked to each individual A7 chip. This extra layer of security means that each iPhone 5s has its own Touch ID harware, which will only work with that specific device. Swapping out the assembly for new parts results in a nonworking Touch ID system.