5G AKA authentication process – (3GPP 33501)

5G AKA authentication process – (3GPP 33501)

Hello my readers today we will talk about two ways to authenticate a UE in 5G :-

5G AKA (Authentication Key Agreement)

EAP AKA

The below components in the 5G network architecture are instrumental in the authentication process

UE – User equipment

SEAF – Security anchor function

AUSF – Authentication server function

UDM – Unified data management

You can consider AUSF as the MME/MSC and UDM as HSS / HLR of the older generation of 3GPP

Here is the step vise authentication process for the UE to the network and vice versa :-

1. On the N1 interface UE send {N1 message with SUCI (if attach for 1st time) else 5G GUTI}

Quick recap on the permanent and temporary identifier used during the attach request and subsequent network usage

2G,3G	4G,5G	Type of subscriber identifier	When is this used
IMSI Internation mobile subscriber identity	SUPI Subscriber permanent identity	Permanent	In order to avoid MITM, only during exceptional scenarios of first time attach Or When the network is unable to resolve SUPI from SUCI/GUTI
TMSI Temparory mobile subscriber identity	GUTI Global unique temparory identifier	Temporary	Each time location is updated or attach attempt is made or call is attempted or as set in the PLMN parameters

HEAV – Home environment authentication vector

AV – Authentication vector

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As you can see now the required keys for session to continue are derived for a session

Kseaf becomes the anchor key to derive Kamf, Knas, Kgnb,Knsiwf

Here the subscriber is successfully authenticated, serving network has been authenticated and the home network has been authenticated. This is the change from earlier generation and added layers of authentication have been added to safeguard the consumer

Do share you comments and let me know, was the article information and definitely i do welcome your comments to further improve the blog…… happy reading