Secure Digital TV Receiver Data Stream Processing
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Solution Overview
Problem
Existing digital TV receivers are vulnerable to unauthorized access due to manipulable clear text data structures, allowing attackers to misidentify stream types and compromise the secure processing of video and audio streams.
Innovation Solution
The method involves decrypting and processing data streams within a secured environment, using encrypted packet identifiers and content type identifiers to ensure secure routing to appropriate decoding modules, and optionally using a hardcoded memory to prevent manipulation, ensuring that only non-manipulatable identifiers are used for processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If clear text PMT and packet headers are used for stream processing, then processing simplicity is improved, but security deteriorates due to manipulability
Solution Approach 1:
The system separates clear text data structures from encrypted data streams, processing them in distinct domains. The PMT and packet headers are handled in a secure domain where manipulation is detected, while decrypted streams are processed in a non-secure domain, preventing attackers from modifying stream identifiers without detection.
Solution Approach 2:
A secure domain acts as an intermediary between the received encrypted streams and the decoding modules. This intermediary verifies the integrity of stream identifiers and routing information before allowing processing, blocking manipulated data from reaching vulnerable components.
2Reliability
If video and audio streams are processed in secured domain, then security is improved, but processing complexity increases due to routing requirements
Solution Approach 1:
The system dynamically determines the processing domain for each decrypted stream based on its content type identifier. Video and audio streams are automatically routed to secured domain processing, while teletext and subtitling streams can be processed outside the secure domain, optimizing both security and resource utilization.
Solution Approach 2:
Different security levels are applied to different processing paths based on the sensitivity of the content. Premium content such as video and audio receives enhanced security processing within the secure domain, while less sensitive content like teletext can be handled with standard processing, creating a differentiated security architecture.
3Productivity
If teletext streams are processed outside secured domain, then processing efficiency is improved, but security deteriorates due to unauthorized access risk
Solution Approach 1:
The system performs preliminary verification of stream identifiers and content type information in the secure domain before routing teletext streams outside the secure domain. This preliminary check prevents manipulated teletext streams from bypassing security controls, maintaining both efficiency and security.
Data Source
AI summary
The invention provides a solution for secure and non-manipulatable processing of a data stream in a receiver, possibly in conjunction with a smartcard. A packet identity and a content type identifier associated with the packet identifier are received in encrypted form and securely processed within the receiver to allow an encrypted payload of the data stream to be processed without the possibility to manipulate the content type identifier in an attempt to intercept the payload after decryption.