SEAF (SEcurity Anchor Function)

Also known as: Security Anchor Function

SEAF is the 5G core function (3GPP TS 33.501) that anchors the primary authentication of the UE and holds the resulting anchor key KSEAF, from which the AMF derives KAMF and further NAS and AS keys. Co-located with the AMF in current deployments, the SEAF isolates long-term key material from serving-network mobility functions and is central to 5G-AKA and EAP-AKA' security.

Categories: Core NetworkSecurity ControlsProtocols and Standards

SEAF in context

The mobile core is where subscriber sessions, mobility and policy live. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

Security controls in telecom span signaling firewalls (SS7/Diameter/GTP screening at the network edge), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both the packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36 and, in Europe, NIS2 sectoral rules.

To place SEAF in the wider telecom-security picture, review N12, UDM, EAP-AKA′, N8, OpenSSL and N3IWF.

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