Section: 5.11.2 Requirements for algorithm selection
Content: a) UE in RRC_Connected and a serving network shall have agreed upon algorithms for - Ciphering and integrity protection of RRC signalling and user plane (to be used between UE and gNB) - Ciphering and integrity protection of RRC signalling and user plane (to be used between UE and ng-eNB) - NAS ciphering and NAS integrity protection (to be used between UE and AMF) b) The serving network shall select the algorithms to use dependent on - the UE security capabilities of the UE, - the configured allowed list of security capabilities of the currently serving network entity c) The UE security capabilities shall include NR NAS algorithms for NAS level, NR AS algorithms for AS layer and LTE algorithms for AS level if the UE supports E-UTRAN connected to 5GC. NOTE: If the UE supports both E-UTRAN and NR connected to 5GC, the UE 5G security capabilities include both the LTE and NR algorithms. d) Each selected algorithm shall be indicated to a UE in a protected manner such that a UE is ensured that the integrity of algorithm selection is protected against manipulation. e) The UE security capabilities shall be protected against "bidding down attacks". f) It shall be possible that the selected AS and NAS algorithms are different at a given point of time.