Certainly something that applies more to cubesats and similar projects. "Normal" satellites typically carry at least an authentication unit that performs some k

Certainly something that applies more to cubesats and similar projects. "Normal" satellites typically carry at least an authentication unit that performs some kind of HMAC checking. You can find some of that stuff here: https://public.ccsds.org/Pubs/352x0b2.pdf https://public.ccsds.org/Pubs/352x0b2.pdf Here's an example of an AU: https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Microelectronics/AUIP https://www.esa.int/Enabling_Support/Space_Engineering_Techn...