Obscuring Audiovisual Data via Sequence Obfuscation
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Solution Overview
Problem
Current copy-protection methods for DVD-Video discs, such as CSS and Macrovision, are easily bypassed by skilled reverse engineers, allowing unauthorized access and copying of audiovisual content, as there are no built-in secure facilities to prevent access to hidden or 'Easter Egg' data.
Innovation Solution
A method and apparatus that divide audiovisual data into cells and sequence instructions, using an access code to control access by calculating a destination structure location within the audiovisual product, employing one-way hash functions and obfuscation techniques to obscure correct sequence instructions among many incorrect ones, and incorporating erroneous 'red herring' cells and video stream switching to secure playback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If built-in copy-protection features (CSS, Macrovision) are used in DVD-Video, then average consumer access is restricted, but skilled reverse engineers can easily bypass these protections
Solution Approach 1:
The audiovisual data is divided into multiple cells, and the sequence instructions are scattered throughout the disc structure. This segmentation makes it difficult for reverse engineers to reconstruct the original content sequence, as the correct sequence is hidden among many incorrect sequences distributed across the disc.
Solution Approach 2:
An access code mechanism is introduced as an intermediary layer between the user and the audiovisual content. The access code controls which sequence instructions are executed, acting as a gatekeeper that prevents unauthorized access while allowing legitimate users to view the content in the correct sequence.
2Adaptability or versatility
If hidden data (Easter Eggs) are included on DVD-Video discs, then user engagement is increased, but reverse engineers can easily access this hidden content without authorization
Solution Approach 1:
Hidden data and Easter Eggs are integrated into the segmented cell structure, where access to these hidden contents is controlled through the same access code mechanism. This allows hidden content to be embedded securely within the segmented structure, making it inaccessible to reverse engineers who cannot obtain the correct access code.
Solution Approach 2:
The access code verification is performed preliminarily before allowing access to any sequence instructions, including those that lead to hidden content. This preliminary action ensures that even hidden data remains protected unless the correct access code is provided, preventing unauthorized access while maintaining user engagement capabilities.
3Productivity
If random access media (DVD, hard drives) are used for storing audiovisual content, then storage capacity and playback speed are improved, but unauthorized viewing and copying become easier
Solution Approach 1:
The audiovisual content stored on random access media is divided into segmented cells with distributed sequence instructions. This segmentation maintains the benefits of random access storage while preventing unauthorized copying, as the segmented structure requires the access code mechanism to reconstruct and play back the content in the correct sequence.
Solution Approach 2:
The access code mechanism serves as an intermediary layer that controls access to the segmented audiovisual data on random access media. This intermediary protection allows the media to maintain its high storage capacity and playback speed advantages while preventing unauthorized viewing and copying through the required access code verification.
Data Source
AI summary
Access to an audiovisual product is controlled by obscuring data. Cells 420 of audiovisual data A, B, C are reproduced by a sequence instruction 410 (e.g. a PGC or Program Chain). One such sequence instruction 410a correctly reproduces the audiovisual data A, B, C, but is hidden amongst many other sequence instructions 410b which incorrectly reproduce the sequence of cells 420 (e.g. as BAC, ACB, CAB, etc.).