Section: 6.1.3.3.1 Synchronization failure or MAC failure in USIM
Content: This clause describes synchronisation failure or MAC failure in USIM. In step 7 in Figure 6.1.3.2-1 when 5G AKA is used; or in step 5 in Figure 6.1.3.1-1 when EAP-AKA’ is used, at the receipt of the RAND and AUTN, if the verification of the AUTN fails, then the USIM indicates to the ME the reason for failure and in the case of a synchronisation failure passes the AUTS parameter (see TS 33.102[ 3G security; Security architecture ]  [9]) to the ME. If 5G AKA is used: The ME shall respond with NAS message Authentication Failure with a CAUSE value indicating the reason for failure. In case of a synchronisation failure of AUTN (as described in TS 33.102[ 3G security; Security architecture ]  [9]), the UE also includes AUTS that was provided by the USIM. Upon receipt of an authentication failure message, the AMF/SEAF may initiate new authentication towards the UE. (see TS 24.501[ Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3 ]  [35]). If EAP-AKA’ is used: The ME shall proceed as described in RFC 4187 [21] and RFC 5448 [12] for EAP-AKA’.