IRS-Assisted Challenge-Response Physical Layer Authentication Scheme Considering Power Budget

Intelligent Reflecting Surface (IRS) assisted challenge-response physical layer authentication (CR-PLA) offers a promising solution for enhancing the security and stability of authentication channels between base stations and legitimate users in wireless environments with obstacles and eavesdroppers. However, there is a tradeoff between communication efficiency and security, with improved security often reducing efficiency. To address this, we propose a power-budget IRS-assisted CR-PLA scheme that balances these competing factors. Our approach involves generating multiple optimal IRS configurations within transmit power budgets and applying them to the authentication channel. We enhance both efficiency and security by randomly employing IRS configurations used for channel reconstruction as a pre-shared key. Experiments demonstrate that our scheme achieves high authentication efficiency and security under power budget constraints. Notably, even if the eavesdropper knows the secret channel configurations in man-in-the-middle attack scenarios, our scheme reduces their authentication success rate by 15.7% to 34.1%, rendering the attack ineffective.