Access Control Message Segmentation for Digital Content
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Solution Overview
Problem
Existing multimedia content transmission networks face challenges in efficiently managing access to encrypted digital content, as access control messages may be incomplete, requiring additional information from users to decrypt the content, which complicates the processing and authorization of access rights.
Innovation Solution
A method that involves receiving an incomplete access control message, obtaining additional information from users to complete it, and using this information to obtain and apply a decryption key for decrypting the digital content, allowing flexible and dynamic access control based on both user-provided information and pre-existing access rights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If access control messages are broadcast in encrypted form with access criteria, then security and access control are improved, but the complexity of processing and authorizing access rights increases
Solution Approach 1:
The patent segments the access control message into two distinct parts: an encrypted portion containing the control word (CW) and an unencrypted portion containing access criteria. This segmentation allows the receiver to first process the unencrypted access criteria to determine eligibility, and only then decrypt the control word if authorized. This resolves the contradiction by maintaining security through encryption while reducing processing complexity through selective decryption based on pre-evaluated access criteria.
2Adaptability or versatility
If incomplete access control messages are transmitted requiring user-provided information, then flexibility in access control is improved, but the difficulty of detecting and measuring complete access rights increases
Solution Approach 1:
The patent implements preliminary action by transmitting the unencrypted access criteria portion of the access control message before requiring user input. The receiver can pre-process and evaluate the access criteria against stored entitlements before prompting the user to provide additional information (such as a personal identification number or secondary authentication). This approach maintains flexibility by allowing adaptive access control while reducing verification difficulty, as the system already has partial validation results before user interaction.
Data Source
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AI summary
Access control is managed for a receiver to access digital content transmitted over a communication network in encrypted form. At the receiver, an access control message (410) associated with the transmitted digital content is received (21). Then, a completed access control message (410) is obtained (22) by adding supplementary information to the completed access control message (410). Next, a decryption key for the digital content is obtained (23) based on the completed access control message. Finally, the transmitted digital content is decrypted (24) using the decryption key thus obtained. The supplementary information is provided by a user.