NBN ISO 21324:2021

This Recommended Standard defines the Security Protocol in terms of:
a) the protocol data units employed by the service provider; and
b) the procedures performed by the service provider.
It does not specify:
a) individual implementations or products;
b) the implementation of service interfaces within real systems;
c) the methods or technologies required to perform the procedures; or
d) the management activities required to configure and control the service.
This Recommended Standard does not mandate the use of any particular cryptographic algorithm with the Security Protocol. Reference [4] provides a listing of algorithms recommended by CCSDS; any organization should conduct a risk assessment before choosing to substitute other algorithms. Annex E (non-normative) defines baseline implementations suitable for a large range of space missions.