Question: In EPS (Evolved Packet System), what is the basis for performing all key derivations, including input parameter encoding, as per 3GPP security architecture specifications?
Option 1: A Key Derivation Function (KDF) specified in a dedicated EPS security standard.
Option 2: AES encryption algorithm with a fixed key size.
Option 3: A universally applied hash function without specific input encoding.
Option 4: Manual key exchange between the UE and the network.
Explanation: The correct answer is Option 1 because, according to the 3GPP security architecture for EPS, all key derivations are standardized to use a specific Key Derivation Function (KDF), ensuring uniformity and security across the system. This KDF is detailed in another 3GPP specification (TS 33.220), emphasizing the importance of standardized security protocols in telecom networks. This approach ensures interoperability and strengthens the overall security posture of EPS by leveraging a vetted, specialized function for key derivation.