Editing My 3GPP 33.501 notes (section)

==== 6.3.2.1 Multiple registrations in different PLMNs ====
The UE shall independently maintain and use two different 5G security contexts, one per PLMN's serving network. Each security context shall be established separately via a successful primary authentication procedure with the Home PLMN.

The ME shall store the two different 5G security contexts on the USIM if the USIM supports the 5G parameters storage. If the USIM does not support the 5G parameters storage, then the ME shall store the two different 5G security contexts in the ME non-volatile memory. Both of the two different 5G security contexts are current 5G security context.

The latest K<sub>AUSF</sub> result of the successful completion of the latest primary authentication shall be used by the UE and the HN regardless over which access network type (3GPP or non-3GPP) it was generated.
 
The HN shall keep the latest K<sub>AUSF</sub> generated during successful authentication over a given access even if the UE is deregistered from that access, but the UE is registered via another access.