1. A computer implemented method for authenticating a user according to the user's biometric features, the method comprising: a) 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; b) detecting, by the processor from a first image of the plurality of images, a plurality of low-level features depicted in the first image; c) determining, by the processor from the first image, a first position of a first low-level feature, wherein the first position is relative to a respective position of each of at least one other low-level feature; d) determining, by the processor from each of at least one other image of the plurality of images, at least one second respective position of the first low-level feature; e) calculating, by the processor as a function of the determining in steps c) and d), changes in position of the first low-level feature; f) generating, by the processor, a biometric identifier that is useable to identify the user as a function of: i) the position of the first low-level feature depicted in the first image, and ii) the calculated changes in position of the first low-level feature; and g) authenticating, by the processor, the user by comparing the biometric identifier to at least one previously generated biometric identifier.