[mrw]

From Apple's support page [1] (Secure Enclave section near the bottom):

> The chip in your device includes an advanced security architecture called the Secure Enclave, which was developed to protect your passcode and fingerprint data. Touch ID doesn't store any images of your fingerprint, and instead relies only on a mathematical representation. It isn't possible for someone to reverse engineer your actual fingerprint image from this stored data.

It's pretty easy to make use of Touch ID for `sudo` authentication, for instance [2].

[1]: https://support.apple.com/en-us/HT204587

[2]: https://news.ycombinator.com/item?id=26302139