The various embodiments described herein include methods, devices, and systems for identifying users. In one aspect, a method includes (1) receiving from a server a request to identify a user; (2) in response to the identification request, sending a request for encoded image data corresponding to one or more features of the first user, the request specifying a particular encoding for the image data; (3) receiving encoded image data corresponding to the one or more features of the first user; (4) obtaining stored image data for an authorized user corresponding to one or more features of the authorized user; (5) determining whether the first user is the authorized user based on a comparison of the received encoded image data and the stored image data; and (6) providing to the remote server an identification indicator based on the determination of whether the first user is the authorized user.