Question: What additional measure could potentially counter a man-in-the-middle attack between the UE and the BSF in the context of TLS authentication, where an attacker has obtained a forged server certificate from a compromised Certification Authority?
Option 1: Implementing channel binding as described in RFC 5929
Option 2: Enhancing HTTP Digest with a more complex password derivation algorithm
Option 3: Utilizing an alternative encryption protocol instead of TLS
Option 4: Increasing the frequency of certificate rotations for the BSF
Explanation: Channel binding, as described in RFC 5929, is specifically designed to mitigate man-in-the-middle attacks by ensuring that the authentication credentials are bound to the secure channel, thereby preventing an attacker from intercepting and reusing them. This measure directly addresses the vulnerability exploited in a man-in-the-middle attack scenario where a forged server certificate has been obtained.