A method achieves secure mobile communications by authenticating a mobile device seeking communication with a secure server. The method prescribes steps for generating a code to indicate a plurality of portions of a digital fingerprint to request from the mobile device, each portion representing a different parameter of the mobile device, sending the code to the mobile device, receiving from the mobile device a response code representing the requested plurality of portions of the digital fingerprint, comparing each portion of the received plurality of portions with one or more predetermined codes, and granting the mobile device an access privilege when results of the comparison satisfy a predetermined minimum accuracy.