Question: During TLS certificate validation in a 3GPP IP-based service, what is the expected outcome if the UE detects changes (other than serial number, validity period, or signature value) in the Root Certificate sent by the P-CSCF compared to the known Root Certificate?
Option 1: The UE will request an updated trusted Root Certificate from the P-CSCF.
Option 2: The UE shall conclude that the certificate verification has failed.
Option 3: The UE will proceed with the connection, assuming the changes are minor.
Option 4: The UE will prompt the user to manually verify the Root Certificate.
Explanation: According to the specified security protocol for IP-based services in 3GPP, if the UE identifies any alterations (beyond the certificate serial number, validity period, or signature value) in the Root Certificate received from the P-CSCF when compared to its pre-known version, it must terminate the verification process with a failure. This stringent measure ensures the integrity and trustworthiness of the communication chain, preventing potential security breaches.