Question: For a UE in an E-UTRA network, which input is NOT required by the PDCP entity for integrity protection of PDUs associated with SRBs and the SLRB?
Option 1: COUNT value
Option 2: Ciphering Key (CK)
Option 3: DIRECTION (direction of transmission)
Option 4: BEARER (radio bearer identifier)
Explanation: The integrity protection function in PDCP for SRBs and SLRB requires inputs like COUNT value, DIRECTION, and BEARER along with a specific KEY (e.g., KRRCint, KUPint, or PIK), but not the Ciphering Key (CK) itself, as CK is used for encryption after integrity protection has been applied.