DRM Source Device Sink Certification via EDID Feedback
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Solution Overview
Problem
Conventional DRM technologies fail to effectively control and certify A/V signals transmitted from a source device to a sink device, allowing for unauthorized access and copying of digital content, and lack the ability to differentiate control based on the type of content or sink device.
Innovation Solution
A DRM system that includes a source device with a DRM module for decrypting multimedia contents and generating control messages to filter and encrypt A/V data based on vendor information from the sink device, allowing differential control of sink devices and secure transmission of A/V signals through DVI or HDMI channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DRM technology encrypts contents and permits access only to licensed source devices, then digital content protection is improved, but the ability to control and certify A/V signals transmitted to sink devices is insufficient
Solution Approach 1:
The DRM system is segmented into two distinct functional layers: content encryption/decryption and A/V signal certification/control. The certification module operates independently from the decryption module, allowing separate control over content access and signal transmission. This segmentation enables the system to maintain strong content protection while adding versatile sink device control capabilities through vendor information-based certification.
Solution Approach 2:
Vendor information (such as EDID data) acts as an intermediary mechanism between the source device and sink device. The certification module uses this intermediary information to identify and control sink devices without requiring direct communication or modification of the content encryption system. This intermediary approach enables adaptive control over multiple sink devices while maintaining the existing DRM content protection framework.
2Object-affected harmful factors
If DRM controls access to encrypted digital contents, then unauthorized copying is prevented, but differential control based on sink device type is not achieved
Solution Approach 1:
The certification module applies local quality control by treating different sink devices differently based on their vendor information. Each sink device receives customized certification decisions according to its specific characteristics (manufacturer, model, capabilities). This allows the system to prevent unauthorized copying universally while simultaneously enabling differential control policies for different device types, such as allowing high-definition output to certified devices while restricting others.
Solution Approach 2:
The certification control is dynamic and adaptable rather than static. The certification module can change its control behavior based on the vendor information received from different sink devices. This dynamic approach enables the system to adaptively grant or deny A/V signal transmission rights according to the specific sink device being accessed, achieving both unauthorized copying prevention and differential control capability.
3Manufacturing precision
If A/V signals are transmitted through DVI or HDMI channels, then high-quality digital transmission is achieved, but unauthorized access at the sink device remains possible
Solution Approach 1:
The certification module performs preliminary action by certifying or rejecting sink devices before A/V signals are transmitted through the DVI or HDMI channels. This pre-certification process checks vendor information and makes authorization decisions in advance, ensuring that only certified sink devices receive the high-quality digital signals. This preliminary control prevents unauthorized access at the sink device while maintaining full transmission quality for authorized devices.
Solution Approach 2:
The system uses feedback from vendor information (such as EDID data returned from sink devices) to control signal transmission. The certification module receives feedback about the sink device's identity and capabilities, processes this information, and uses it to make authorization decisions. This feedback mechanism enables the system to maintain high transmission quality through DVI/HDMI channels while preventing unauthorized access by verifying sink device credentials before signal transmission.
Data Source
AI summary
A source device and a method are provided for certifying and controlling A/V signals output from an A/V device through an output terminal of a digital visual interface (DVI) or a high definition multimedia interface (HDMI), using Digital Rights Management (DRM). The source device includes: a DRM module which decrypts encrypted multimedia contents included in DRM contents through certification of a source device, and generates a control message for controlling digital A/V channels connected between the source device and a sink device based on a DRM rule; an input controller which certifies A/V data input from a media decrypter, and outputs A/V data filtered according to a certifying result; an input interface which converts the filtered A/V data into pixel data and audio data; and a signal transmitter which encrypts and converts the pixel and audio data into high-speed serial digital A/V signals to be transmitted to the sink device.