Benefits of Biometrics
Biometrics balance security and convenience. Access is instant, yet harder to spoof than a weak password.
Implementation on iOS
Use the LocalAuthentication framework. Check for availability (biometryType). Handle FaceID usage description in Info.plist.
Implementation on Android
Use the BiometricPrompt API for a consistent system UI. It supports fingerprint, face, and iris across different manufacturers.
Secure Key Storage
Don't just stay "logged in". Use biometrics to unlock an encrypted token in Keychain/Keystore. The hardware confirms identity; the system releases the key.
When to Use It
Use for app unlock, authorizing payments, or accessing sensitive settings. Don't replace the initial password setup.
Fallback Mechanisms
Biometrics can fail (wet fingers, masks). Always offer a PIN or Password fallback. Never rely 100% on biometrics.
Privacy Considerations
Biometric data never leaves the device's secure enclave. Reassure users of this privacy fact in your UI.