Controllable Asymmetric Attack Against Practical Round-Trip Fiber Time Synchronization System

Using optical fiber links to transmit time information is widely regarded as an accurate and secure time synchronization scheme. However, the accuracy of the round-trip time synchronization system can be manipulated arbitrarily by attack schemes. In this paper, a controllable asymmetric attack scheme against round-trip time synchronization system is proposed and experimentally demonstrated. By adjusting the asymmetry of the link, the time synchronization accuracy can be controlled down from 23 ps to 0.91 ns, 2.13 ns and 5.20 ns. Our work reveals system vulnerability caused by asymmetry, and points out that current systems can be attacked unwittingly by adversaries.