A method includes storing a reference fingerprint for a first device in a database; operating a second device in an identity authentication mode; receiving, by the second device while operating in the identity authentication mode, a signal transmission from an unknown device; determining, by the second device, a fingerprint for the unknown device based on the signal transmission; responsive to the fingerprint of the unknown device matching the reference fingerprint for the first device, processing a data packet associated with the signal transmission; and responsive to the fingerprint of the unknown device not matching the reference fingerprint for the first device, ignoring the data packet associated with the signal transmission.