olemus
ISO/IEC 11770-5:
loogiline struktuur võtme halduseks,
ei ole seotud võrgu topoloogiaga
=
logical structure to manage keys
Note. The choice of the logical key hierarchy is independent of the network topology.

standard
https://cdn.standards.iteh.ai/samples/75295/ee802ffc54e74946adf15b68caae6fcc/ISO-IEC-11770-5-2020.pdf