Question: In a Generic Bootstrapping Architecture (GBA) scenario, what is the expected behavior of the Universal Integrated Circuit Card (UICC) upon receiving an authentication request from the Mobile Equipment (ME) recognized as related to GBA_U?
Option 1: The UICC shall derive the bootstrapping key and immediately transmit it to the ME for further processing.
Option 2: The UICC shall only authenticate the request without deriving any new keys, relying on existing 3G AKA keys (CK and IK).
Option 3: The UICC shall derive the bootstrapping key but store it locally without sharing it with the ME, from which NAF-specific keys can be further derived upon request.
Option 4: The UICC shall reject authentication requests for GBA_U if no previous 3G AKA session has been established.
Explanation: According to GBA principles, when the UICC recognizes an authentication request as related to GBA_U, it enhances security by containing sensitive operations within the secure environment of the UICC. Deriving and locally storing the bootstrapping key (without sharing with the ME) ensures sensitive materials are not exposed. This aligns with securing 3G AKA keys (CK and IK), implying a similar stance for derived GBA keys, supporting localized processing.