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Guide

What is liveness detection?

Face matching tells you two faces look alike. Liveness tells you there's a real, present person in front of the camera. You need both.

Man holding a printed photo of himself — a classic spoofing attempt

Key takeaways

  • Presentation attacks include prints, screen replays and masks.
  • Passive liveness is low-friction; active liveness adds assurance.
  • Injection attacks bypass the camera and need capture-integrity controls too.
  • Look for evaluation against ISO/IEC 30107-3.

Why matching isn't enough

A fraudster with a victim's photo can hold it up to the camera. A pure match will happily say "same person". Liveness — formally presentation attack detection — catches that before the match counts.

Types of attack

  • Print attacks: a photo on paper, sometimes with the eyes cut out.
  • Replay attacks: a video played on a phone or monitor.
  • Mask attacks: paper, silicone or 3D-printed masks.
  • Injection attacks: synthetic or deepfake video fed directly into the app or a virtual camera, never touching a lens.

Passive vs active

Passive liveness analyses a single frame or short clip for texture, depth and reflection cues — the user just takes a selfie. Active liveness asks for an action like turning the head. Many teams run passive by default and step up to active for risky sessions.

Standards and testing

ISO/IEC 30107-3 defines how presentation attack detection is tested and reported. When evaluating vendors, ask what attack types were tested, by whom, and at what error rates.

Best practices

  • Run liveness and matching on the same capture.
  • Combine with device signals to resist injection attacks.
  • Give clear capture guidance — lighting and framing matter.
  • Route borderline scores to manual review rather than auto-rejecting.

Try it with the SIMSIM liveness API.

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