How are authorizations made only by Apple ID?

Question

iOS

Good afternoon.
Here, usually, authorization occurs on the part of the user, that is, he enters his email, mobile number and password. And there are applications that do not torment the user, authorization occurs automatically. As far as I understand, this is through an Apple ID. This is true?
You don't even need to enter a password! After all, you can just put a finger, well, or a face).
Please explain how it works. I would like some theory and articles, if of course they are.
Thank you very much in advance!)

Answer 1

This is not called Apple ID, but Touch ID and Face ID - technologies for biometric authorization of a person in the system. The system has a so-called API - an interface for interacting with the system, it was created specifically for developers - so that they can use the system to one hundred percent. Touch ID and Face ID are just parts of this interface. Biometrics is implemented by sensors of the same name - Face ID and Touch ID. The scanner in the button creates a mathematical representation of your fingerprint and the processor performs the calculations for identification. From the well-known facts, I allow myself to assume that scanners are, roughly speaking, ordinary sensors and neural networks. There is nothing complicated about this - Apple can even attach a breathalyzer to the pipe and authorize it only by the presence of a certain degree of intoxication in you and your blood. Their software