authentication

Automate iOS authentication flows with Sign in with Apple, OAuth, and biometric re-authentication.

Updated Apr 19, 2026

Search Tags:#authentication #oauth #biometrics #keychain #signin-with-apple #aswebauthenticationsession

Ready to run

npx skills add https://github.com/femitz/flyby --skill authentication-femitz

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: authentication
Source: https://github.com/femitz/flyby/tree/main/.agents/skills/authentication
Command: npx skills add https://github.com/femitz/flyby --skill authentication-femitz

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

Implementing robust authentication flows on iOS across Sign in with Apple, OAuth, password AutoFill, and biometric re-authentication, with secure token handling.

Core Features & Use Cases

Sign in with Apple integration (ASAuthorizationAppleIDProvider, ASAuthorizationController, ASAuthorizationAppleIDCredential)
Credential state checks and revocation handling
OAuth flow via ASWebAuthenticationSession
Password AutoFill support with ASPasswordCredential
Biometric authentication via LAContext for sign-in and re-auth
Server-side identity token validation and Keychain storage
Existing account setup flows on app launch to silently restore sessions
SwiftUI SignInWithAppleButton integration example
Secure token storage best practices

Quick Start

Integrate Sign in with Apple, OAuth, and biometric authentication in your iOS app and secure tokens in the Keychain for server validation.

Frequently Asked Questions about authentication

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I implement Sign in with Apple in a SwiftUI app?▼

To implement Sign in with Apple in SwiftUI, use the SignInWithAppleButton to trigger the ASAuthorizationAppleIDProvider flow, retrieve the ASAuthorizationAppleIDCredential, and store tokens in the Keychain for server validation.

How does ASWebAuthenticationSession handle OAuth flows on iOS?▼

ASWebAuthenticationSession manages iOS OAuth flows by presenting a secure browser context for user authentication, capturing the callback URL, and securely extracting authorization codes for Keychain token storage.

Can I use LAContext for biometric re-authentication after initial sign-in?▼

Yes, LAContext enables biometric re-authentication after initial sign-in by verifying Face ID or Touch ID, allowing apps to silently restore sessions or secure sensitive actions without requiring users to re-enter credentials.

What is the best way to securely store OAuth tokens in an iOS app?▼

The best way to securely store OAuth tokens in an iOS app is using the Keychain, which provides encrypted credential storage for server-validated identity tokens and enables silent session restoration during app launch.

Why do I need to check credential state with ASAuthorizationAppleIDProvider?▼

You need to check credential state with ASAuthorizationAppleIDProvider to detect token revocation, ensuring your app handles sign-outs properly and removes stored Keychain tokens when users disconnect their Apple ID.

Does iOS password AutoFill work with ASPasswordCredential?▼

Yes, iOS password AutoFill works with ASPasswordCredential to streamline existing account setup flows, allowing users to authenticate quickly by selecting saved credentials during app onboarding or sign-in.