—In recent times, the importance of information security in civilian space communication systems has increased significantly among space agencies. Those systems often require a high degree of flexibility, interoperability and scalability. Therefore the usage of traditional, physical layer based security solutions is not a desirable option for the agencies. In this paper, we investigate the application of security services to the CCSDS Packet TM/TC space communication protocol stack and propose a transparent and open solution that provides an optimal trade-off between security, interoperability and technical implementation feasibility. We take into consideration the special restrictions that are superimposed by the space environment and existing legacy systems.