Question: In a multi-connection mode setup over a TWAN access, what additional key is derived from the EMSK by the 3GPP AAA Server and sent to the TWAP, for protecting WLAN Control Protocol (WLCP) between the UE and TWAG?
Option 1: MSK (Master Session Key)
Option 2: EPS (Encapsulating Security Payload) Key
Option 3: WLCP (WLAN Control Protocol) Key
Option 4: EAP (Extensible Authentication Protocol) Key
Explanation: In the context of multi-connection mode over a TWAN access, for securing WLAN Control Protocol (WLCP) communication between the User Equipment (UE) and the Trusted WLAN Access Gateway (TWAG), an additional key specifically designed for this purpose is utilized. This key, known as the WLCP Key, is derived from the Extended Master Session Key (EMSK) by the 3GPP Authentication, Authorization, and Accounting (AAA) Server. The WLCP Key is then shared with the Trusted WLAN AAA Proxy (TWAP) to ensure secure setup and teardown of PDN connections, highlighting its unique role in protecting WLCP exchanges.