Biometric security systems use unique physical characteristics, such as fingerprints, facial recognition, or iris scans, to authenticate users. These systems capture biometric data, which is then converted into a digital format and stored for matching during authentication attempts. When a user tries to access a secure system, their biometric input is compared against the stored data to verify identity. This method enhances security, as biometrics are difficult to replicate or forge compared to traditional passwords. Biometric systems are increasingly utilized in various applications, including mobile devices, secure facilities, and border control.