Liveness detection verifies that a biometric trait (fingerprint, palm‑vein, facial or iris scan) comes from a live person rather than a fake replica, using cues such as blood flow, skin texture or depth mapping; the captured data is instantly turned into an encrypted, non‑reversible template that stays on the terminal, and any static spoof (gel finger, printed image, video) fails the check. This, combined with tamper‑resistant hardware security modules and end‑to‑end encryption, ensures only a genuine user can unlock the stored payment token, protecting biometric payments from fraud.