Question: In a Service Based Architecture (SBA) deployment, what is crucial for securing the underlying virtualized infrastructure hosting SBA Network Functions (NF), in addition to endpoint authentication?
Option 1: Only Confidentiality of signaling messages
Option 2: Integrity and Replay Protection of user data
Option 3: Confidentiality, Integrity, and Replay Protection between authenticated endpoints
Option 4: Secure Storage of Subscriber Data
Explanation: In an SBA deployment, especially in a multivendor, all-software environment, ensuring the security of the virtualized infrastructure is paramount. This involves not just securing the communication between authenticated endpoints but also guaranteeing the confidentiality (protecting against unauthorized access), integrity (ensuring data isn't modified without authorization), and replay protection (preventing the reuse of previously sent messages) of the information exchanged. This comprehensive approach safeguards against a wide range of potential threats, making **Option 3** the most appropriate answer.