Question: What is the primary function of the LENGTH indicator in the 3GPP security architecture?
Option 1: To determine the number of encryption rounds.
Option 2: To specify the type of encryption algorithm used.
Option 3: To determine the length of the required keystream block.
Option 4: To authenticate the user equipment.
Explanation: The LENGTH indicator is a 16-bit value that determines the length of the keystream block, which is essential for secure data transmission in telecom networks.