Biometric authentication (Face ID, Touch ID) in iOS Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is biometric authentication in iOS?

Biometric authentication uses a person's unique physical traits, like Face ID or Touch ID, to unlock apps or devices securely without typing passwords.

beginner

Which iOS framework is used for biometric authentication?

The LocalAuthentication framework provides tools to check and use Face ID or Touch ID for user authentication.

intermediate

What is the purpose of LAContext in biometric authentication?

LAContext is an object that manages authentication policies and evaluates if biometric authentication can be performed on the device.

intermediate

How do you check if biometric authentication is available on an iOS device?

Use LAContext's canEvaluatePolicy method with LAPolicy.deviceOwnerAuthenticationWithBiometrics to check if Face ID or Touch ID is supported and enrolled.

beginner

What happens if biometric authentication fails or is not available?

You should provide a fallback like device passcode authentication or manual login to keep the app accessible and secure.

Which class in iOS handles biometric authentication requests?

A UIViewController

B UIApplication

C LAContext

D CLLocationManager

LAContext is the class used to manage biometric authentication policies and requests.

What does Face ID use to authenticate a user?

A PIN code

B Fingerprint scan

C Voice recognition

D Facial recognition

Face ID uses facial recognition technology to authenticate users.

Which method checks if biometric authentication can be used?

A evaluatePolicy

B canEvaluatePolicy

C authenticateUser

D checkBiometrics

canEvaluatePolicy checks if the device supports and has biometric authentication set up.

If biometric authentication is not available, what should an app do?

A Ask for device passcode or password

B Ignore authentication

C Crash immediately

D Restart the device

Apps should provide a fallback like device passcode or password to keep users able to log in.

Which framework must be imported to use Face ID or Touch ID in Swift?

A LocalAuthentication

B AVFoundation

C CoreData

D UIKit

LocalAuthentication framework provides biometric authentication features.

Explain how to implement biometric authentication in an iOS app using Swift.

Think about the steps from checking availability to performing authentication.

Describe why providing a fallback method is important when using biometric authentication.

Consider what happens if Face ID or Touch ID is not set up or fails.