1. A method to authenticate a live person subject, comprising: receiving an authentication request from a user; generating, in response to the authentication request, a sequence of instructions instructing the user to point a face of the user toward a sequence of facial directions, wherein the sequence of facial directions are randomly generated using a random sequence generation algorithm, wherein the sequence of facial directions correspond to a sequence of reference facial images of the live person subject; presenting the sequence of instructions to the user, comprising: presenting a first instruction at a first time point, wherein the first instruction instructs the user to point the face toward a first facial direction; and presenting a second instruction at a second time point, wherein the second instruction instructs the user to point the face toward a second facial direction, wherein the first time point and the second time point are determined based on instruction delays randomly generated using the random sequence generation algorithm; capturing, while presenting the sequence of instructions to the user, a sequence of live-captured facial images (LCFIs) based on a pre-determined frame rate; and generating an authentication result identifying the user as the live person subject by at least: matching a LCFI in the sequence of LCFIs to a first reference facial image of the live person subject toward the first facial direction; and matching another LCFI in the sequence of LCFIs to a second reference facial image of the live person subject toward the second facial direction; and validating each LCFI in the sequence of LCFIs based on a pre-determined criterion.