The CCSDS Space Data Link Security protocol

The Consultative Committee for Space Data Systems (CCSDS) initiated work several years ago to develop a knowledge-base and relevant standards for the protection of the Telecommand and Telemetry communications and data systems of space missions of their Member Space Agencies. A particularly recent CCSDS security effort concerns the development and specification of a Space Data Link Security (SDLS) protocol that can provide security services to the existing CCSDS family of Space Data Link (SDL) protocols: Telecommand (TC), Telemetry (TM) and Advanced Orbiting Systems (AOS). Those CCSDS SDL protocols are used extensively for Telecommand as well as for both Housekeeping and Payload Telemetry space links by the entire civil space community. While ad-hoc security implementations have been developed by several CCSDS Member Agencies, there is a recognition that a commonly engineered security protocol with minimal logical and physical integration impact on CCSDS space data link protocols and compatible with Space Link Extension (SLE) protocols would be very beneficial not only for CCSDS Member Agencies but also for commercial space missions, space data handling equipment suppliers and possibly other future applications such as civilian Unmanned Aerial Vehicles (UAV) data links. This paper will describe the protocol requirements, the provided security services, issues concerning its implementation and integration/interface with TM, TC and AOS data link protocols as well as its current development status.