Question: What is the primary purpose of the SQNMS and SQNHE counters in the authentication mechanism between the USIM and the network?
Option 1: To synchronize the encryption keys (CK and IK) between the USIM and the HLR/AuC.
Option 2: To support mutual authentication by tracking sequence numbers for network authentication.
Option 3: To manage the storage of multiple secret keys (K) within the USIM.
Option 4: To validate the Authentication Management Field (AMF) in the authentication token (AUTN).
Explanation: The correct answer is Option 2 because SQNMS (stored in the USIM) and SQNHE (stored in the HLR/AuC) are counters used to support network authentication, ensuring that the sequence numbers are correctly synchronized to prevent replay attacks, thus facilitating secure mutual authentication. This highlights their role in practical telecom scenarios for securing user-network interactions.