1. A computer-implemented method, comprising: receiving, by a computing device at a first time period, a first image frame including a first representation of at least a portion of a face; analyzing the first image frame to determine that the first representation corresponds to an identity authorized to access the computing device; receiving, by the computing device at a second time period, image data including a plurality of representations of at least the portion of the face; analyzing the image data frame to determine a rate of coloration change of the plurality of representations; determining that the rate of coloration change corresponds to a heart rate associated with a living human; and granting access to a functionality of the computing device requiring authentication.