Security Dictionary (Security)¶

A dictionary for looking up the key terms of 5GC security by meaning and usage. For the detailed flows, see the Authentication chapter / Security chapter.

Related: Authentication chapter / Security chapter / Identifier Dictionary / NF Dictionary

Authentication/key terms¶

Algorithm/procedure terms¶

Diagram: key hierarchy tree¶

This puts the derivation relationships from the table above into a single tree. Lower keys are derived from higher keys, and the lower a key sits the narrower the scope (segment) it protects. The key point is that KAMF branches into the keys for NAS (terminated at the AMF) and KgNB, the starting point for AS (terminated at the gNB).

flowchart TB
    KSEAF["KSEAF
Top-level anchor key
(AUSF→SEAF on successful authentication)"]
    KAMF["KAMF
(held by the AMF)"]
    subgraph NAS["For NAS (terminated between UE ⇔ AMF)"]
        direction LR
        KNI["KNASint
NAS integrity"]
        KNE["KNASenc
NAS encryption"]
    end
    KGNB["KgNB
Starting point for AS
(to the gNB)"]
    subgraph AS["AS = for radio (terminated between UE ⇔ gNB)"]
        direction LR
        KRI["KRRCint
RRC integrity"]
        KRE["KRRCenc
RRC encryption"]
        KUI["KUPint
UP integrity"]
        KUE["KUPenc
UP encryption"]
    end

    KSEAF --> KAMF
    KAMF --> KNI
    KAMF --> KNE
    KAMF --> KGNB
    KGNB --> KRI
    KGNB --> KRE
    KGNB --> KUI
    KGNB --> KUE

    classDef anchor fill:#fde,stroke:#c69,stroke-width:2px;
    classDef nas fill:#eef,stroke:#66a;
    classDef as fill:#efe,stroke:#3a3;
    class KSEAF,KAMF anchor;
    class KNI,KNE nas;
    class KRI,KRE,KUI,KUE as;