Question: What are the two authentication protocols used for UE-BSF authentication, ensuring secure communication, where one is a mandatory legacy protocol and the other provides an additional layer of security?
Option 1: IKEv2 and IPsec
Option 2: GSM AKA (2G AKA) only
Option 3: TLS with server certificates only
Option 4: GSM AKA (2G AKA) + TLS with server certificates
Explanation: The correct answer combines both required protocols for UE-BSF authentication. GSM AKA (2G AKA) is mandated as the base authentication protocol, leveraging the security of cellular subscription verification. Additionally, TLS with server certificates provides an extra layer of encryption and trust, ensuring the authenticity of the BSF. This dual approach enhances the overall security posture of the authentication process between the User Equipment (UE) and the Bootstrapping Server Function (BSF).