Question: During S1 or X2 handover in a 3GPP network, what happens to the S-KWT (Security Key for Wireless Terminal) and its derived keys when the LWA (LWIP - Light Weight IP) DRB (Dedicated Radio Bearer) connection between the UE (User Equipment) and WT (Wireless Terminal) is released?
Option 1: The UE updates the S-KWT with new keys derived from the target cell's identifiers.
Option 2: The UE retains the S-KWT but only updates the derived keys for the new bearer context.
Option 3: The network requests the UE to re-establish the S-KWT after the handover is complete.
Option 4: The UE deletes the S-KWT and further keys derived based on it.
Explanation: This is correct because, according to the security architecture for handover procedures in 3GPP networks, when the LWA DRB connection is released during S1 or X2 handover, the UE must delete the existing S-KWT and all keys derived from it to ensure security integrity. This process prevents potential security breaches by not carrying over sensitive key material to a new, potentially different, security context.