1. A computer-assisted method for identifying a person, comprising: receiving data solely encoding a digitally watermarked digital facial portrait of the person, wherein the digitally watermarked digital facial portrait is embedded with at least one digital watermark identifying payload data linking the digital facial portrait to the person portrayed in the digital facial portrait; receiving results of comparison between data received that solely encodes the digital facial portrait of the person and the person presenting the digitally watermarked digital facial portrait on a display of a mobile computing device; scanning the digitally watermarked digital facial portrait being displayed on the mobile computing device such that the at least one digital watermark is decoded in response to receiving comparison results that the person portrayed in the digital facial portrait is the person presenting the digitally watermarked digital facial portrait on the mobile computing device; and determining that the digital facial portrait is authentic based on the decoded at least one digital watermark by (i) retrieving personally identifiable information based on the identified payload data; and (ii) authenticating the displayed digital facial portrait based on the retrieved personally identifiable information.