What is AUSF ?
The AUSF is the 5G Core network function responsible for authenticating User Equipment attempting to connect to the network. It implements 5G-AKA (Authentication and Key Agreement) and EAP-AKA’ protocols, generating the security keys that protect all subsequent communications.
How Does AUSF Work?
When a UE initiates registration, the AMF contacts the AUSF. The AUSF retrieves authentication vectors from the UDM (via the Nudm interface), runs the authentication challenge-response exchange with the UE, and generates the KSEAF anchor key used to derive subsequent encryption and integrity keys. It exposes the Nausf service interface.
Use Cases
Authenticating every 5G subscriber on network attach, generating security keys for NAS and AS encryption, roaming authentication between home (HPLMN) and visited (VPLMN) networks.
3GPP / Standards Reference
3GPP TS 33.501 (5G Security Architecture), TS 29.509 (Nausf Service Definition)
Related Terms
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