5G-AKA
5G Authentication and Key Agreement: the primary authentication procedure in 5G using challenge-response with the home network's AUSF and UDM for mutual authentication.
5G-AKA is the default way a 5G subscriber and the home network prove themselves to each other. It's a challenge-response built on the symmetric key K that's shared between the USIM and the home network's UDM/ARPF — nobody else ever holds it. The home network generates an authentication vector, the UE computes a response from the challenge and its key, and the two sides check each other. Crucially it's mutual: the UE authenticates the network too, which blocks rogue base stations from impersonating a real one.
The 5G twist over EPS-AKA is where confirmation happens. The home network doesn't just hand the visited network a green light to give out; the UE's response is verified back at the home AUSF, and the home network gets explicit confirmation that the UE authenticated. That home-control property makes it much harder for a visited or fraudulent network to fake a successful authentication on the home operator's behalf. The procedure also seeds the whole key hierarchy used for NAS and AS security afterwards.
Frequently asked questions
- What is the difference between 5G-AKA and EAP-AKA'?
- Both authenticate using the symmetric key on the USIM and produce the same anchor key for the key hierarchy, so security-wise they're close. The differences are framing and use. 5G-AKA is the streamlined 3GPP-native procedure used over 3GPP access. EAP-AKA' runs the authentication inside the IETF EAP framework, which is what you need for non-3GPP access (like trusted/untrusted Wi-Fi via an N3IWF) and gives a cleaner binding to the access network. Operators can use either over 3GPP access; EAP-AKA' is mandatory for non-3GPP.
Related terms
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