Physical-Layer Challenge-Response Authentication with IRS and Multi-Antenna Devices

This thesis investigates the use of Intelligent Reflecting Surfaces (IRS) in physical-layer authentication (PLA), with a specific focus on challenge-response (CR) mechanisms. IRS is a promising technology which enables to control and reconfigure wireless propagation channels. The IRS is under the control of the receiver (Bob), whose goal is to verify the identity of the transmitter. In fact, Bob randomly configures the IRS and then verifies that the result- ing estimated channel is correspondingly modified. The CR-PLA scheme is evaluated in terms of the trade-off between communication and security per- formance, measured by the channel capacity and the probabilities of false alarms (FA) and missed detections (MD), respectively. In particular, we aim at designing the probability distribution of the random IRS configuration that maximizes the ergodic capacity under an upper bound constraint on the average misdetection and false alarm probabilities.