A.12 KNG-RAN* derivation function for target ng-eNB

A.12 K_NG-RAN* derivation function for target ng-eNB

33.5013GPPRelease 18Security architecture and procedures for 5G SystemTS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

When deriving a K_NG-RAN* from current K_gNB or from fresh NH and the target physical cell ID in the UE and NG-RAN for handover purposes and transition from RRC_INACTIVE to RRC_CONNECTED states the following parameters shall be used to form the input S to the KDF.

– FC = 0x71

– P0 = PCI (target physical cell id)

– L0 = length of PCI (i.e. 0x00 0x02)

– P1 = EARFCN-DL (target physical cell downlink frequency)

– L1 = length of EARFCN-DL (i.e. 0x00 0x03)

The input key KEY shall be the 256-bit NH when the index NCC in the handover increases, otherwise the current 256-bit K_gNB (when source is gNB) or K_eNB (when source is ng-eNB).