Core - N12,N13 - AMF,AUSF,UDM - Authentication

Technical details of the authentication process in 5G networks, focusing on the core components N12 and N13, and the entities involved: AMF (Authentication Management Function), AUSF (Authentication Server Function), and UDM (Unified Data Management).

1. Authentication Management Function (AMF - N12):
   • The AMF is a key element in the 5G core network responsible for managing authentication and security functions.
   • When a user equipment (UE) initiates a connection request, the AMF is involved in the initial steps of the authentication process.
2. Authentication Server Function (AUSF - N13):
   • The AUSF is another critical component that plays a central role in the authentication process.
   • AUSF stores authentication data and handles authentication vectors, which are used to authenticate the UE.
   • It communicates with the AMF to provide authentication information during the UE registration process.
3. Unified Data Management (UDM - N13):
   • The UDM is responsible for managing subscriber data, including authentication credentials and other user-related information.
   • In the context of authentication, the UDM stores and manages the permanent authentication data for the subscriber.
4. Authentication Process Steps:
   • When a UE initiates a connection request, the AMF generates a request for authentication information.
   • The AMF communicates with the AUSF to obtain authentication vectors.
   • The AUSF generates and sends authentication vectors to the AMF. These vectors are temporary values used for the authentication process.
   • The AMF forwards the authentication vectors to the UE.
   • The UE uses the received authentication vectors to generate a message (Authentication Request) and sends it to the AMF.
   • The AMF validates the authentication request by checking the received message against the authentication vectors it obtained from the AUSF.
   • If the authentication is successful, the AMF considers the UE authenticated and proceeds with establishing the connection.
5. Security Algorithms:
   • The authentication process involves the use of security algorithms such as AKA (Authentication and Key Agreement) to ensure the confidentiality and integrity of the authentication procedure.
   • AKA involves the generation and verification of authentication vectors, which include random challenges, to authenticate the UE.
6. Key Generation:
   • As part of the authentication process, session keys are generated to establish secure communication between the UE and the network.
   • These keys are derived from the authentication vectors exchanged during the authentication process.

The authentication process in 5G involves the interaction of key entities (AMF, AUSF, UDM) and the use of authentication vectors and security algorithms to ensure the secure and reliable connection of the UE to the 5G network.