Question: What is the primary requirement for the re-synchronization message authentication function f1* in terms of cryptographic properties?
Option 1: It should be able to encrypt large amounts of data efficiently.
Option 2: It must ensure it's computationally infeasible to derive the key (K) from known inputs (SQN, RAND, AMF) and output (MAC-S or XMAC-S).
Option 3: It needs to support both symmetric and asymmetric encryption methods.
Option 4: Its primary goal is to provide a secure key exchange between UE (User Equipment) and the RAN (Radio Access Network).
Explanation: The correct answer highlights the essential property of a Message Authentication Code (MAC) function like f1*, ensuring the secrecy of the key (K). This means with knowledge of SQN, RAND, AMF, and MAC output, it should be computationally infeasible to deduce the original key (K), crucial for network security, preventing unauthorized access, and ensuring communication integrity.