SOS: Standard-Compliant and Packet Loss Tolerant Security Framework for ADS-B Communications

The Automatic Dependent Surveillance - Broadcast (ADS-B) technology, already deployed by the major avionics companies (e.g., QatarAirways and AmericanAirlines), will become mandatory on board of civil and military aircraft flying in Class A, B, and C airspaces by 2020, enabling direct airplanes communications and enhanced flights monitoring. However, ADS-B has been designed without security considerations, thus being vulnerable to a variety of attacks, including message injection and messages order manipulation attacks, that can be easily performed via widely available commercial Software Defined Radios. To address these threats, we present Securing Open Skies (SOS), a standard-compliant, backward-compatible, loss-tolerant, and bandwidth efficient security framework to secure ADS-B communications. SOS leverages the real deployment of densely distributed, participatory ADS-B sensor networks such as OpenSky Network and Flight Radar, and provides message authentication and integrity security services on a time-slot basis, without resorting to any public key cryptography mechanism. Experimental performances obtained through a realistic proof-of-concept, deployed using commercial Ettus Research X310 Software Defined Radios, demonstrate the viability and effectiveness of our solution, even in presence of uniformly at random or burst packet loss events characterizing the ADS-B frequency band. For instance, SOS allows the verification of the authenticity of ADS-B messages requiring less than 50 percent of bandwidth overhead, with a percentage of verifiable slots above 80 percent, even in an highly lossy environment, characterized by a single packet loss probability of 60 percent - the process requiring less than one second: almost one tenth of similar approaches published in the literature. Finally, a thorough comparison against state of the art solutions in the literature highlights the unique security and reliability features enjoyed by SOS, as well as its practical viability.