Question: What is the primary purpose of deriving HASHMME and HASHUE in the 3GPP System Architecture Evolution (SAE) security architecture, and what input parameter from the UE's initial request is used in this derivation process?
Option 1: To authenticate the MME and UE identities, utilizing the UE's IMSI as the primary input parameter.
Option 2: To encrypt subsequent NAS messages, using the UE's IP address as a key component in the KDF input.
Option 3: To validate the integrity of the initial request, employing the unprotected ATTACH Request or TAU Request message (S) as a critical input to the Key Derivation Function (KDF).
Option 4: To authorize QoS settings for the UE, with the input being the requested bandwidth in the initial attach.
Explanation: The correct answer is Option 3 because HASHMME and HASHUE are derived to ensure the integrity and authenticity of the unprotected ATTACH Request or TAU Request message from the UE. This process involves using the message as an input to a Key Derivation Function (KDF), highlighting the importance of message integrity in the initial stages of network attachment in the SAE security architecture.