A Study of Covert Communications in Space Platforms Hosting Government Payloads

: In recent years, unmanned space vehicles have increasingly become targets of cyber-attacks. Exacerbating the problem is the desire to reduce cost and accelerate access to space by hosting government-supplied payloads on commercial space platforms. These commercially hosted payloads require stringent confidentiality protection and encryption alone is not sufficient to protect against illegal information leakage on a spacecraft with multilevel security (cross-domain) capabilities. Covert channels may still exist and be exploited by colluding entities to communicate secretly via shared resources. This report describes a preliminary study of potential covert channels in communications protocols used in satellites--specifically MIL-STD-1553B and SpaceWire.