1. A computer implemented method for authenticating a user according to the user's biometric features, the method comprising: capturing, by a mobile device having a camera, a storage medium, instructions stored on the storage medium, and a processor configured by executing the instructions, a plurality of images depicting at least one facial region of the user, capturing, by the processor and a microphone communicatively coupled to the processor, an audio data file including a recording of the user's voice, wherein the audio data file is captured concurrent to capturing the plurality of images by the processor using the camera; detecting, by the processor from a first image of the plurality of images, a plurality of facial features depicted in the first image; determining, by the processor from the first image, a first position of the facial features, wherein the first position of each facial feature is relative to a respective position of each of at least one other facial feature; determining, by the processor from each of at least one other image of the plurality of images, at least one second respective position of each of the facial features; calculating, by the processor as a function of determining the first position and the at least one second respective position, changes in position of each of the facial features; generating, by the processor from the audio data file, a voice print characterizing the user's voice and usable to identify the user; generating, by the processor, a first biometric identifier that is useable to identify the user as a function of the first position of the facial features and, wherein the generating step includes encoding, in the first biometric identifier, intensity values for a plurality of pixels depicting respective facial features detected in the first image as spatial gradients; encoding, in at least one biometric identifier, the calculated changes in position of the facial features as temporal gradients, wherein the temporal gradients correspond to the pixels depicting respective facial features detected in the first image, and wherein the temporal gradients represent a difference between a location of the pixels depicting respective facial features in the first image and respective locations of pixels depicting the respective facial features in the at least one other image; authenticating, by the processor, the user by: comparing the first biometric identifier to at least one previously generated biometric identifier, comparing the voice-print to at least one previously generated voice-print, and comparing the calculated changes in position of the facial features to the voice-print; generating, by the processor in response to authenticating the user, an identity verification request that includes information identifying the user and the mobile device, and includes an indication that the user has been biometrically authenticated by the mobile device; transmitting, by the processor to a remote server device over a network, the identity verification request thereby prompting the remote server device to verify the user identity; receiving, by the processor from the remote server device in response to the identity verification request, a notification that the user identity has been further verified by the remote server; and generating, by the processor, an authentication notification responsive to the user authentication and the identity verification notification.