1. A computer-implemented method for detecting user liveness comprising: illuminating, by an illumination device included in a computing device, the face of a user, the illumination being randomly varied over time between different colors in the visible spectrum; capturing, by the computing device, face biometric data from the user as a sequence of images; transmitting, by the computing device, the captured face biometric data to an authentication computer system over a network; recognizing, by the authentication computer system, illumination characteristics in the captured face biometric data caused by the illumination; and determining, by the authentication computer system, the user is live when the recognized illumination characteristics match the illumination characteristics expected to be caused by the illumination.