A.22 KTIPSec and KTNAP derivation function

A.22 K_TIPSec and K_TNAP derivation function

33.5013GPPRelease 18Security architecture and procedures for 5G SystemTS

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

When deriving a K_TIPSec from K_TNGF and when deriving a K_TNAP from K_TWIF or K_TNGF the following parameters shall be used to form the input S to the KDF.

– FC = 0x84

– P0 = Usage type distinguisher

– L0 = length of Usage type distinguisher (i.e. 0x00 0x01)

The values for the Usage type distinguisher are defined in table A.22-1. The values 0x00 and 0x03 to 0xf0 are reserved for future use, and the values 0xf1 to 0xff are reserved for private use.

The Usage type distinguisher shall be set to the value for IPSec (0x01) when deriving K_TIPSec. The Usage type distinguisher shall be set to the value for TNAP (0x02) when deriving K_TNAP.

The input key KEY shall be the 256-bit K_TNGF or K_TWIF.

Table A.22-1: Usage type distinguishers

Usage type distinguisher	Value
IPSec	0x01
TNAP	0x02