Biometric Authentication

Biometric authentication lets a user sign in to an app or confirm an action with a fingerprint or face instead of a password. The match happens on the device, using the platform APIs, and the biometric data never leaves the hardware.

The security depends on tying the biometric check to something real, such as releasing a key from the keystore or keychain only after a successful match. A check that just returns true or false in app code can be bypassed, so testing confirms it is bound to a protected operation.