Current Setup:
Using Secure Enclave with userPresence access control
Foreground keychain accessibility: whenPasscodeSetThisDeviceOnly
Security Requirement:
Our security group wants us to invalidate biometrics and require a username/password if a biometric item is added (potentially by a hostile 3rd party)
Need to upgrade from userPresence to biometricCurrentSet to ensure re-authentication when biometric credentials change.
Issue:
After implementing biometricCurrentSet, authentication cancels after two failed biometric attempts instead of falling back to passcode.
Current Detection Method:
User completes initial biometric authentication
Biometric changes occur (undetectable by app)
App attempts Secure Enclave access
Access denial triggers re-authentication requirement
Cannot revoke refresh token after access is denied
Security Concern:
Current implementation allows new biometric enrollments to access existing authenticated sessions without re-verification.
Question:
What's the recommended approach to:
Implement biometricCurrentSet while maintaining passcode fallback
Properly handle refresh token invalidation when biometric credentials change
Looking for guidance on best practices for implementing these security requirements while maintaining good UX.