Face ID asks for permission when first requested

Number:rdar://35554298 Date Originated:15-Nov-2017 09:54 AM
Status:Closed Resolved:
Product:iOS + SDK Product Version:11
Classification:UI/Usability Reproducible:Always
The first time Face ID authentication is requested using the LocalAuthentication APIs a permission prompt appears. This is inconsistent with Touch ID and goes against a HIG recommendation:

> If biometric authentication is enabled at the system level, just assume the user wants to use it.

Following this advice, apps that show Face ID authentication on app launch will get confusing behavior because on first launch the user is first presented with a permission dialog.

Steps to Reproduce:
1. Call context.evaluatePolicy with deviceOwnerAuthenticationWithBiometrics

Expected Results:
The user is to authenticate with Face ID

Actual Results:
The user is asked whether they want to allow “App Name”  to use Face ID.




Klaas Pieter Annema

My app does not prompt display an explicit prompt. LocalAuthentication does. See attached screen recording and sample project.

The iPhone 7 immediately asks for TouchID, whereas the iPhone X first prompts whether the user wants to allow FaceID and then asks for FaceID itself.

Apple Developer Relations

Please know that our engineering team has determined that this issue behaves as intended based on the information provided.

An app shouldn't explicitly display a prompt. It's fine if the system does, however. If an app displays a prompt too, then the user ends up getting prompted twice the first time FaceID authenticates.

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