Question: What is the minimum number of digits required for a PIN (including PIN2) used for user verification in a 3GPP application, and how are shorter PINs handled?
Option 1: Minimum 6 digits; shorter PINs are rejected by the ME.
Option 2: Minimum 4 digits; if less than 8, the ME pads the presented PIN with 'FF' before sending it to the 3GPP application.
Option 3: Minimum 8 digits; no padding is applied for shorter PINs.
Option 4: Variable length; the ME determines the required length based on the UICC type.
Explanation: A PIN (including PIN2) in a 3GPP application must have at least 4 digits. If a user presents a PIN with fewer than 8 digits, the Mobile Equipment (ME) pads this PIN with 'FF' before transmitting it to the 3GPP application, ensuring consistency in PIN length for processing.