Section: 5.2.2 User data and signalling data confidentiality
Content: The UE shall support ciphering of user data between the UE and the gNB. The UE shall activate ciphering of user data based on the indication sent by the gNB. The UE shall support ciphering of RRC and NAS-signalling. The UE shall implement the following ciphering algorithms: NEA0, 128-NEA1, 128-NEA2 as defined in Annex D of the present document. The UE may implement the following ciphering algorithm: 128-NEA3 as defined in Annex D of the present document. The UE shall implement the ciphering algorithms as specified in TS 33.401[ 3GPP System Architecture Evolution (SAE); Security architecture ]  [10] if it supports E-UTRA connected to 5GC. Confidentiality protection of the user data between the UE and the gNB is optional to use. Confidentiality protection of the RRC-signalling, and NAS-signalling is optional to use. Confidentiality protection should be used whenever regulations permit.