A.3 Derivation of CP-PRUK ID*

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

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

– FC = 0x86;

– P0 = "PRUK-ID";

– L0 = length of "PRUK-ID";

– P1 = relay service code;

– L1 = length of relay service code;

– P2 = SUPI;

– L2 = length of SUPI.

The input key KEY is K_{AUSF_P}.