Exploring the potential of longitudinal power monitoring for detecting physical-layer attacks [Invited]

The recurring cases of suspicious incidents involving optical fiber cables in recent years have exposed the vulnerabilities of modern communication networks. Whether driven by geopolitical tensions, sabotage, or urban vandalism, these disruptions can cause Internet blackouts, compromise user privacy, and, most critically, challenge operators’ reliability in delivering secure connectivity. Moreover, the emergence of such incidents raises key concerns about how effectively network operators can secure thousands of kilometers of deployed fiber without incurring additional costs from expensive monitoring solutions. In this context, the rise of receiver (Rx)-based digital signal processing (DSP) monitoring schemes can serve as a valuable ally. Originally designed for optical performance monitoring—providing insights such as the estimation of the longitudinal power monitoring (LPM) in optical fiber links—these approaches can also play a crucial role in detecting fiber-related attacks, as any attempt to leak or degrade information leaves distinctive optical power signatures that can be revealed by the Rx-DSP. Therefore, this work investigates the effectiveness of LPM in detecting physical-layer attacks. A detailed simulative analysis is conducted for fiber tapping, addressing aspects such as monitoring implementation, security vulnerabilities, and signature recognition. Other attacks, such as quality-of-service degradation and out-of-band jamming via gain competition, are explored qualitatively, offering insights and identifying opportunities for future research.