Multiprocessor Conditional Access Module Security Architecture
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Solution Overview
Problem
Existing conditional access modules (CAMs) are vulnerable to unauthorized access attacks due to external means exploiting the system input/output interface, which can compromise microprocessor memory and functionality, leading to potential unauthorized decryption of media programs.
Innovation Solution
A multi-processor design with an interface module that processes communications between the CAM and a receiver, presenting a single virtual processor externally, with each processor having its own non-volatile memory to enforce security policies and complicate attacks by generating independent responses to access requests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single processor is used in the CAM, then the device complexity is reduced, but the security against external attacks is compromised
Solution Approach 1:
The patent divides the CAM into multiple independent processors (first processor and second processor) that operate separately. Each processor has its own memory and execution path, segmenting the system to increase security by requiring multiple independent components to be compromised simultaneously for unauthorized access.
Solution Approach 2:
The interface module acts as an intermediary between external attackers and the internal processors. It presents a unified interface to the outside world while managing communications with multiple internal processors, adding a layer of abstraction that complicates external attacks.
2Reliability
If multiple processors are used in the CAM, then the security against external attacks is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple processors (first processor and second processor) into a single CAM unit that presents a unified interface externally. The interface module combines the outputs of multiple processors into a single response, merging their functionality while maintaining the security benefits of multiple independent processing paths.
3Reliability
If an interface module is added to process communications, then the security against internal attacks is improved, but the device complexity increases
Solution Approach 1:
The interface module serves as an intermediary layer between external communications and the internal processors. It processes all incoming messages, distributes them to appropriate processors, and aggregates responses, adding a layer of security by preventing direct access to processor memory and instructions.
Solution Approach 2:
The interface module segments communication functions from processing functions. By separating the communication interface from the processor memory space, it creates a boundary that prevents external means from directly accessing or modifying processor instructions and data.
4Reliability
If processor commands are distributed to multiple processors, then the decryption security is improved, but the processing time increases
Solution Approach 1:
The decryption process is segmented into independent operations distributed across multiple processors. Each processor handles specific decryption tasks independently, allowing parallel processing that reduces total time while maintaining security through the distributed architecture.
Solution Approach 2:
Multiple processors can operate continuously on different aspects of decryption simultaneously. The interface module coordinates these continuous operations to ensure that decryption progress is maintained without idle time, optimizing the balance between security and processing efficiency.
Data Source
AI summary
A system and method of controlling access to a media program via a receiver communicably coupleable to a conditional access module is described. The apparatus comprises a first processor, a second processor, and an interface module, communicatively coupled to the first processor and the second processor, the interface module for processing all communications with the conditional access module and externally manifesting a single virtual processor to the receiver.