The method behind is a challenge-response protocol. By challenging the user with displayed actions and validating whether the response are followed in the right order, the actual presence of a live face is ensured. Challenges typically includes eyes blinking, head rotation and mouth movement.

The non-intrusive mechanism is based on the idea of further improving the user's experience and operation efficiency. By facing the screen for a second, a liveness check is confirmed.

The main proposal is to emit light of random colors, capture the light reflected from the face and match the result. In particular, the user do not need to perform any extra steps. A good reliability as well as user experience is guaranteed.