Secure Motion Verification using the Doppler Effect

Matthias Schäfer, Patrick Leu, Vincent Lenders, Jens Schmitt

Future transportation systems highly rely on the integrity of spatial information provided by their means of transportation such as vehicles and planes. In critical applications (e.g. collision avoidance), tampering with this data can result in life-threatening situations. It is therefore essential for the safety of these systems to securely verify this information. While there is a considerable body of work on the secure verification of locations, movement of nodes has only received little attention in the literature. This paper proposes a new method to securely verify spatial movement of a mobile sender in all dimensions, i.e., position, speed, and direction. Our scheme uses Doppler shift measurements from different locations to verify a prover’s motion. We provide formal proof for the security of the scheme and demonstrate its applicability to air traffic communications. Our results indicate that it is possible to reliably verify the motion of aircraft in currently operational systems with an equal error rate of zero.

Review:
This paper proposes a scheme for verifying motion claims (i.e., speed and direction) of mobile devices. The problem is motivated by the criticality of spatial information in vehicular and aerial transportation systems (e.g., unauthenticated ADS-B air transportation system). The proposed scheme relies on measuring the doppler shift by multiple receivers to detect fabricated claims. The authors show that with two verifiers (receivers) the adversary is significantly limited (to a hyperbola) and with three verifiers the adversary is further restricted and will be detected unless if at least two verifiers are on a straight line from the perspective of the claimed location.

The reviewers appreciated that the paper is grounded in theoretically sound techniques, and that the authors built a complete system using the Ettus USRP X300 and experimented with real data from the ADS-B air transportation system. They put significant effort in adapting the proposed scheme and optimizing it for real wireless communication constraints (extending existing libraries such as the OpenSky one), as well as identifying adequate thresholds for low false-positives and negatives. The reviewers expressed some doubts about the approach, e.g., the lack of resiliency to an adversary equipped with multiple antennas.