H.6 Derivation of Kc128 and Ki128

3GPP43.020Release 16Security related network functionsTS

MS and eSGSN derive the control plane and user plane ciphering key (Kc128) and the control plane and user plane integrity protection key (Ki128) from CK and IK. Ki128 shall only be derived by the MS and the network when using enhanced GPRS in relation to CIoT as specified in the present Annex.

The key Kc128 is specified in TS 33.102 Annex B [18].

The key Ki128 shall be used as an input only to the GIA integrity protection algorithms which require 128-bit key.

The derivation of the key Ki128 shall use the Key Derivation Function (KDF) specified in TS 33.220 [22].

The Key to be used in key derivation shall be the concatenation of CK and IK. The KDF returns a 256-bit output, where the 128 least significant bits are identified with Ki128.

– FC = 0x38

No input parameters (Pi, Li) are used by this function.