  The physical layer authentication (PLA) is a promising technology which can
enhance the access security of a massive number of devices in the near future.
In this paper, we propose a reconfigurable intelligent surface (RIS)-assisted
PLA system, in which the legitimate transmitter can customize the channel
fingerprints during PLA by controlling the ON-OFF state of the RIS. Without
loss of generality, we use the received signal strength (RSS) based spoofing
detection approach to analyze the feasibility of the proposed architecture.
Specifically, based on the RSS, we derive the statistical properties of PLA and
give some interesting insights, which showcase that the RIS-assisted PLA is
theoretically feasible. Then, we derive the optimal detection threshold to
maximize the performance in the context of the presented performance metrics.
Next, the actual feasibility of the proposed system is verified via
proof-of-concept experiments on a RIS-assisted PLA prototype platform. The
experiment results show that there are 3.5% and 76% performance improvements
when the transmission sources are at different locations and at the same
location, respectively.
