Question: In a Network Domain Security (NDS) Authentication Framework, what is a specific requirement for the private key used to sign the PKIMessage in a Certificate Confirm request, following an initialization or key update response?
Option 1: The private key must be newly generated for each Certificate Confirm request.
Option 2: The private key can be any valid key associated with the base station's certificate.
Option 3: The private key must be the same one used in the preceding initialization or key update request.
Option 4: The private key is not required for signing the PKIMessage in this specific scenario.
Explanation: This requirement ensures continuity and authenticity, linking the Certificate Confirm request directly to the previous initialization or key update process. Using the same private key for signing maintains a secure association between these sequential messages, enhancing the trust in the authentication framework within telecom networks.