  In Internet of Things, where billions of devices with limited resources are
communicating with each other, security has become a major stumbling block
affecting the progress of this technology. Existing authentication
schemes-based on digital signatures have overhead costs associated with them in
terms of computation time, battery power, bandwidth, memory, and related
hardware costs. Radio frequency fingerprint (RFF), utilizing the unique
device-based information, can be a promising solution for IoT. However,
traditional RFFs have become obsolete because of low reliability and reduced
user capability. Our proposed solution, Metasurface RF-Fingerprinting Injection
(MeRFFI), is to inject a carefully-designed radio frequency fingerprint into
the wireless physical layer that can increase the security of a stationary IoT
device with minimal overhead. The injection of fingerprint is implemented using
a low cost metasurface developed and fabricated in our lab, which is designed
to make small but detectable perturbations in the specific frequency band in
which the IoT devices are communicating. We have conducted comprehensive system
evaluations including distance, orientation, multiple channels where the
feasibility, effectiveness, and reliability of these fingerprints are
validated. The proposed MeRFFI system can be easily integrated into the
existing authentication schemes. The security vulnerabilities are analyzed for
some of the most threatening wireless physical layer-based attacks.
