Public key infrastructure for air traffic management systems

Next generation air traffic management (ATM) systems will rely on secure air-ground and ground-ground communications links. These links will be secured using a combination of commercial-off-the-shelf (COTS) techniques, (e.g., using the Internet IPsec standards), as well as techniques unique to the aviation community, (i.e., using aeronautical telecommunications network (ATN) security). In either case, as the supporting networks grow in size and as the number of aircraft using security grows, it is apparent that symmetric key pairs cannot be maintained for all combinations of participating entities. Rather, a general public key infrastructure (PKI) must be employed to handle the general problem of large-scale key distribution. This paper first introduces basic concepts of asymmetric cryptography, authentication, public key certificates, and a public key infrastructure. Next, a general description of how the public key infrastructure supports an Air Traffic Management environment is provided. Finally, the issue of cross-certification is described using the air-ground communications environment as an example.