3GPP 24.501 v20.0.0 — the document's own text

5.4.1.1 General

Taught in 6. Getting on the network, and getting a connection through it (CT1 — the group that writes what your phone says, in depth), 10. Who CT1 writes to, and what the letters count (CT1 — the group that writes what your phone says, in depth), 12. The neighbours — and how little the record says about them (CT1 — the group that writes what your phone says, in depth), 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).

The purpose of the primary authentication and key agreement procedure is to enable mutual authentication between the UE and the network and to provide keying material that can be used between the UE and network in subsequent security procedures, as specified in 3GPP TS 33.501 [24].

Two methods are defined:

EAP based primary authentication and key agreement procedure.
5G AKA based primary authentication and key agreement procedure.

The UE and the AMF shall support the EAP based primary authentication and key agreement procedure and the 5G AKA based primary authentication and key agreement procedure.