Content for TS 33.535 Word version: 18.4.0

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5.1 AKMA key hierarchy 5.2 AKMA key lifetimes
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5 Key management p. 14

5.1 AKMA key hierarchy p. 14

The key hierarchy (see Figure 5.1-1) includes the following keys: KAUSF, KAKMA, KAF. KAUSF is generated by AUSF as specified in clause 6.1 of TS 33.501.

Keys for AAnF:

KAKMA is a key derived by ME and AUSF from KAUSF.

Keys for AF:

KAF is a key derived by ME and AAnF from KAKMA.

KAKMA and KAF are derived according to the procedures of clauses 6.1 and 6.2.

Reproduction of 3GPP TS 33.535, Fig. 5.1-1: AKMA Key Hierarchy

Figure 5.1-1: AKMA Key Hierarchy

5.2 AKMA key lifetimes p. 15

The KAKMA and A-KID are valid until the next successful primary authentication is performed (implicit lifetime), in which case the KAKMA and A-KID are replaced.

AKMA Application Keys KAF shall use explicit lifetimes based on the operator's policy. The lifetime of KAF shall be sent by the AAnF as described in clauses 6.2 and 6.3. In case that a new AKMA Anchor Key KAKMA is established, the AKMA Application Key KAF can continue to be used for the duration of the current application session or until its lifetime expires, whichever comes first. When the KAF lifetime expires, a new AKMA Application Key is established based on the current AKMA Anchor Key KAKMA.