5G • Security
K_gNB
Base Station Root Security Key
Radio access security root key derived by AMF from K_AMF and delivered to the gNodeB over N2.
Technical Explanation
The AMF computes K_gNB = KDF(K_AMF, NAS COUNT) and securely pushes it to the serving gNodeB inside the NGAP Initial Context Setup message. The gNodeB never sees K_AMF or K_SEAF. From K_gNB, the base station derives all over-the-air AS encryption and integrity keys.
Key Functions
- Cryptographic root key for the radio access network (gNodeB)
- Pushed from AMF to gNodeB over secure N2 NGAP signaling
- Parent key for all over-the-air RRC and user plane encryption keys
Specifications
3GPP TS 33.501, TS 38.413
Interfaces
N2Uu
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