TV Set Back Box Dual-Channel Authentication via HDMI and USB

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Solution Overview

Problem

The existing communication protocols between TVs and set top boxes/set back boxes, such as HDMI, are vulnerable to data exchange compromises due to slow data exchange rates and potential spoofing via USB channels, which can undermine HDCP encryption.

Innovation Solution

Establishing a dual communication channel system using both HDMI and a secondary channel like USB, where a TV sends an encryption data element like a HDCP key or random number over HDMI and receives it back through the secondary channel to authenticate and ensure secure communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a single HDMI communication channel is used between TV and set box, then the system is simple and easy to operate, but data exchange is slow and security is compromised due to potential spoofing attacks

Engineering Contradiction:

Improvedata exchange speedVSAvoidcommunication channel structure

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The communication system is segmented into two distinct channels: HDMI channel for video/audio data transmission and USB channel for control commands and icon exchange. This segmentation allows each channel to be optimized for its specific function, improving overall data exchange speed while maintaining system security through the TV-generated random number verification mechanism on the USB channel

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A TV-generated random number acts as an intermediary verification element. The TV sends this random number through the HDMI channel to the set box, and the set box must return the same random number through the USB channel to prove authentic identity. This intermediary mechanism enables fast data exchange on HDMI while ensuring security without compromising either speed or simplicity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If HDCP encryption is implemented over HDMI channel, then content protection is improved, but security can be compromised if a PC spoofs the TV into thinking it is a set box

Engineering Contradiction:

Improvecontent protection reliabilityVSAvoidspoofing attacks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The TV generates and sends a random number to the set box through the HDMI channel before content transmission begins. This preliminary action establishes an authentication challenge that the set box must respond to correctly through the USB channel, preventing spoofing attacks before they can compromise HDCP encryption

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the TV sends a random number challenge to the set box, and the set box must return the correct response through the USB channel. This feedback loop verifies the set box's authentic identity, ensuring that only legitimate set boxes can receive protected content while maintaining strong HDCP encryption

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7856104B2System and method for ensuring secure communication between TV and set back box

Publication Date: 2010.12.21 SATURN LICENSING LLC

AI summary

A random number or HDCP key is sent from a TV to a set back box (SBB) over a HDMI channel, and unless the SBB returns the same random number/key to the TV over a USB link, the TV will not communicate further with the SBB.