Section: 5.9.2.1 Security Requirements for service registration, discovery and authorization
Content: NF Service based discovery and registration shall support confidentiality, integrity, and replay protection. NRF shall be able to ensure that NF Discovery and registration requests are authorized. NF Service based discovery and registration shall be able to hide the topology of the available / supported NF's in one administrative/trust domain from entities in different trust/administrative domains (e.g. between NFs in the visited and the home networks.) NF Service Request and Response procedure shall support mutual authentication between NF Service Consumer and NF Service Producer. Each NF shall validate all incoming messages. Messages that are not valid according to the protocol specification and network state shall be either rejected or discarded by the NF.