O-TSN: Enabling Oblivious Traffic Switch for Time-Sensitive Networking

Time-sensitive networking (TSN) empowers industrial automation by providing deterministic, low-latency, and low-jitter network communication. Paradoxically, regarding security, such determinism leaks the arrival times of critical traffic (e.g., robotic arm coordination and vehicle brake control), which is exploited to launch side-channel attacks in real-time systems. Considering this, we first identify that TSN is vulnerable to traffic- and memory-based side-channel attacks, and then validate that these attacks can successfully reveal the arrival times of all critical traffic. As a countermeasure, we propose Oblivious TSN (O-TSN), a secure TSN framework that protects the arrival times of critical traffic without over-affecting their performance. We devise two sub-protocols, traffic obfuscation and oblivious priority queues, providing differential privacy and oblivious security, respectively. We formally define the security of O-TSN and ensure strong privacy guarantees by injecting dummy frames while introducing only bounded latency and jitter. We develop a prototype of O-TSN and thoroughly evaluate it on both simulation and Alinx AX7021 boards as real-world hardware. Results show that, compared to standard TSN, our traffic obfuscation forwards all critical traffic in time with 99.5% of original performance, and oblivious queues incur deterministic latency and jitter <0.5ms.