Question: In a Generic Bootstrapping Architecture (GBA) scenario, what is the primary purpose of the SBA interfaces exposed by the Bootstrap Server Function (BSF)?
Option 1: To authenticate User Equipment (UE) for network access
Option 2: To manage Quality of Service (QoS) for GBA-enabled applications
Option 3: To provide bootstrap information for deriving application key material (e.g., Ks_(ext/int)_NAF)
Option 4: To handle billing and charging for GBA-based services
Explanation: The correct answer is Option 3 because, in the context of Generic Bootstrapping Architecture (GBA), the Bootstrap Server Function (BSF) exposes SBA interfaces specifically to share bootstrap information. This shared information is crucial for the Network Application Function (NAF) to derive application-specific key material, such as Ks_(ext/int)_NAF, which is essential for securing application-level communications. This process ensures secure key exchange and authentication between the UE's application and the NAF, highlighting the importance of bootstrap information in GBA for security.