Question: What protocol is utilized between the UICC Hosting Device and the Bootstrapping Server Function (BSF) at reference point Ub for key establishment?
Option 1: HTTP Digest AKA (Authentication and Key Agreement)
Option 2: TLS (Transport Layer Security) with EAP-SIM
Option 3: DTLS (Datagram Transport Layer Security) with PSK (Pre-Shared Key)
Option 4: IPsec (Internet Protocol Security) with IKEv2
Explanation: The correct answer is HTTP Digest AKA because it is employed for communication between the UICC Hosting Device and the BSF, enabling mutual authentication and key agreement to generate the bootstrapping key Ks, crucial for securing subsequent communications.