Display device with mobile high-definition link port and signal processing method thereof

A signal processing method for a display device, the display device being feasible to connect to a human interface device (HID) and a portable consumer electronic device via a mobile high-definition link (MHL) port, the signal processing method comprising:

• a) providing a set of encryption codes to the portable consumer electronic device via a communication bus (CBUS) in the MHL port;
• b) determining whether the portable consumer electronic device passes authentication according to an encrypted identification fed back from the portable consumer electronic device, wherein the encrypted identification is generated by the portable consumer electronic device according to the set of encryption codes;
• c) if the portable consumer electronic device passes the authentication, when the HID provides a user command to the display device, rearranging and encrypting the user command according to the set of encryption codes to generate an encrypted user command compliant with a CBUS specification;
• and
• d) providing the encrypted user command to the portable consumer electronic device via the CBUS in the MHL port, the user command configured to cause the portable consumer electronic device to change what is displayed on a display of the portable consumer electronic device.