Abstract

The development of connected vehicles (CVs) provides a great opportunity for new vehicle-to-infrastructure (V2I) applications, such as optimizing traffic signal in real-time based on CV data. However, such connectivity at transportation infrastructure also implies potential vulnerability in cyber-attacks. This paper proposes a generic trajectory-based hierarchical defense (TBHD) framework to protect transportation infrastructure under trajectory spoofing attacks. The trajectory spoofing attacks are indirect cyber-attacks in which falsified Basic Safety Messages (BSMs) from CVs are sent to roadside units to influence V2I applications. Based on the knowledge of vehicle dynamics and trajectory cross-validation, the TBHD framework aims at detecting and filtering falsified trajectory data (i.e., BSMs) from compromised CVs. The TBHD framework consists of three levels of defenses. Level 1 is a pointwise checking that checks if data elements in the received BSMs fall within their feasible ranges. Level 2 is a multiple-point checking that checks if the consecutive BSMs of a CV obey the laws of physics. Level 3 is a multiple-trajectory checking that checks if two CVsâ?? trajectories overlap with each other. Three sets of simulation studies were conducted to evaluate the performance of the defense framework at each level with different traffic demands and defense frequencies. Results reveal that the proposed defense framework can filter most of the data spoofing attacks. The development of a generic defense system is necessary to safeguard the transportation infrastructure in a connected environment.