Nested Rights Verification Messages for Secure Content Access
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Solution Overview
Problem
Current access control systems for protected audiovisual content lack sophistication and flexibility, particularly in combining access criteria and managing rights across different devices and formats, leading to security vulnerabilities and interoperability issues.
Innovation Solution
A method involving nested rights verification messages, where each message contains an access criterion and an encrypted decryption key, allowing for sequential testing of access criteria across multiple devices and formats, ensuring a well-defined execution path and enhancing security without modifying existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple access criteria tests are performed sequentially using nested rights verification messages, then access control security and flexibility are improved, but message structure complexity and processing overhead increase
Solution Approach 1:
The patent implements nested rights verification messages where ECM messages are embedded within other ECM messages, creating a hierarchical structure. Each nested ECM contains access criteria and encrypted control words that must be sequentially decrypted. This nesting approach allows multiple access criteria to be tested in a single message transmission, improving security without requiring separate message exchanges for each criterion.
Solution Approach 2:
The access control process is segmented into multiple sequential stages, each corresponding to a nested ECM layer. The system divides the overall access verification into discrete steps where each layer tests specific access criteria independently. This segmentation allows the system to maintain complex security requirements while providing structured, manageable processing at each stage.
2Adaptability or versatility
If nested rights verification messages are used to test multiple access criteria, then service possibilities and access flexibility are improved, but processing time and computational resources increase
Solution Approach 1:
The system performs preliminary decryption of nested ECM messages in sequence, where each successfully decrypted layer prepares the next layer for decryption. Access criteria are tested in advance through the nested structure, allowing the system to quickly determine compatibility before full content decryption. This preliminary verification reduces wasted processing on incompatible access requests.
Solution Approach 2:
The decryption process maintains continuous useful action by chaining the decryption of nested ECM messages together. Each successfully decrypted ECM immediately enables the decryption of the next nested ECM, creating an unbroken sequence of useful operations. This continuity maximizes processing efficiency by avoiding idle states between verification steps.
3Adaptability or versatility
If access control is distributed across multiple devices using nested messages, then system adaptability and interoperability are improved, but coordination complexity and communication overhead increase
Solution Approach 1:
The nested ECM message structure serves multiple functions simultaneously: it acts as both an access control container and an encryption carrier, functions as both a verification mechanism and a key distribution vehicle. This multi-functionality allows the same message structure to be used across different devices and systems without requiring device-specific message formats, thereby improving interoperability while managing coordination complexity.
Data Source
Figure 1~5A
Figure 2A
Figure 2B
AI summary
The invention relates to a method for monitoring access to protected audiovisual content, wherein a message, including N rights verification messages (ECM1, ECM2, ) placed one inside the other and command messages i with 1 = i = N, is received. The command message i contains an ith access criterion (CA_Entrance) and the command rights verification message i+1 in encrypted form. The command message N includes an Nth access criterion (CA_Inside) and a protected audiovisual content decryption key (CW), itself encrypted. For the command message i, i initially taking the value 1, a test (351) is carried out to verify if rights associated with a device satisfy the ith access criterion. If testing positive for the i index, the instruction message i+1 is decrypted and a repetition of said test for index i+1 is requested. If testing positive for the N index, the protected audiovisual content decryption key (CW) is accessed (354).