Section: 5.3.3 User data and signalling data integrity
Content: The gNB shall support integrity protection and replay protection of user data between the UE and the gNB. The gNB shall activate integrity protection of user data based on the security policy sent by the SMF. The gNB shall support integrity protection and replay protection of RRC-signalling. The gNB shall support the following integrity protection algorithms: - NIA0, 128-NIA1, 128-NIA2 as defined in Annex D of the present document. The gNB may support the following integrity protection algorithm: - 128-NIA3 as defined in Annex D of the present document. Integrity protection of the user data between the UE and the gNB is optional to use, and shall not use NIA0. NOTE: Integrity protection of user plane adds the overhead of the packet size and increases the processing load both in the UE and the gNB. NIA0 will add an unnecessary overhead of 32-bits MAC with no security benefits. All RRC signalling messages except those explicitly listed in TS 38.331[ NR; Radio Resource Control (RRC); Protocol specification ]  [22] as exceptions shall be integrity-protected with an integrity protection algorithm different from NIA0, except for unauthenticated emergency calls. NIA0 shall be disabled in gNB in the deployments where support of unauthenticated emergency session is not a regulatory requirement.