A.4 NH derivation function

33.4013GPP3GPP System Architecture Evolution (SAE)Release 17Security architectureTS

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

When deriving a NH from K_ASME the following parameters shall be used to form the input S to the KDF.

– FC = 0x12

– P0 = SYNC-input

– L0 = length of SYNC-input (i.e. 0x00 0x20)

The SYNC-input parameter shall be the newly derived K_eNB for the initial NH derivation, and the previous NH for all subsequent derivations. This results in a NH chain, where the next NH is always fresh and derived from the previous NH.

The input key shall be the 256-bit K_ASME.