A.2 CP-PRUK derivation function

33.5033GPPRelease 17Security Aspects of Proximity based Services (ProSe) in the 5G System (5GS)TS

When deriving a CP-PRUK from K_{AUSF_P}, the following parameters shall be used to form the input S to the KDF:

– FC = 0x85;

– P0 = SUPI;

– L0 = length of SUPI;

– P1 = relay service code;

– L1 = length of relay service code.

The input key KEY is K_{AUSF_P}.

SUPI shall have the same value as parameter P0 in clause A.7.0 of TS 33.501 [3].