NAF (Network Application Function)

Also known as: Network Application Function

In the 3GPP Generic Bootstrapping Architecture, the NAF is the application server that consumes a GBA-derived key (Ks_NAF) to authenticate a UE without holding long-term subscriber credentials itself. The NAF fetches the key material from the BSF over the Zn/Zn' reference point after the UE has bootstrapped, and uses it to secure the application session.

Categories: Security ControlsProtocols and StandardsEncryption and Cryptography

NAF in context

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.

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how the specs interlock (for example 3GPP TS 33.501 with GSMA FS.34 for 5G SBA security), is essential for both design and audit work.

To place NAF in the wider telecom-security picture, review N8, SRTP, GBA, HKDF, XMPP and DTLS-SRTP.

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