Fine Grain Rights Management for Streaming Content
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Solution Overview
Problem
Current Digital Rights Management (DRM) systems for wireless broadcast services lack fine-grained control over usage rights for streaming content, as they can only specify one set of rights for a validity period, which is insufficient for varying content types and time-dependent access restrictions.
Innovation Solution
The method involves delivering a separate encrypted key stream message with each time slice burst of data, allowing each portion of the encrypted stream to be decrypted using a corresponding traffic key, and using a program category variable in the Rights Expression Language to dynamically adjust usage rights based on content categories, enabling more precise and flexible usage rights management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single set of usage rights is provided for the entire validity period of a Rights Object, then the system complexity is reduced and bandwidth consumption is minimized, but the fine-grained control over different content types and time periods is lost
Solution Approach 1:
The patent segments the usage rights control into multiple Rights Objects with different validity periods, each containing specific usage rights for different content types or time periods. This allows fine-grained control without requiring a single complex rights management system to handle all scenarios simultaneously.
Solution Approach 2:
The system dynamically selects and applies different Rights Objects based on the current content type and time period. The Rights Expression Language enables dynamic evaluation of usage conditions, allowing the system to adapt rights application in real-time without manual intervention.
2Measurement precision
If multiple Rights Objects with different usage rights are delivered frequently to enable fine-grained control, then usage right precision is improved, but bandwidth consumption increases
Solution Approach 1:
The patent pre-defines multiple Rights Objects with different usage rights before they are needed. These pre-prepared rights objects can be quickly selected and applied when specific content types or time periods occur, eliminating the need for real-time rights generation and reducing bandwidth consumption.
Solution Approach 2:
The system changes the validity period parameter of Rights Objects to match the specific time periods or content types being delivered. By adjusting this parameter, the system can provide precise usage rights control without requiring continuous updates to rights information, thereby reducing bandwidth consumption.
3Speed
If the service key changes frequently to enable quick channel switching, then system responsiveness is improved, but the frequency of key updates increases bandwidth consumption
Solution Approach 1:
The patent segments the key management into traffic keys for frequent changes (enabling quick channel switching) and service keys for less frequent changes (reducing bandwidth consumption). The Rights Objects contain service keys that remain valid for extended periods, while only the traffic keys need to be updated frequently for channel switching.
Solution Approach 2:
The patent introduces an intermediary key hierarchy where service keys act as mediators between the frequent traffic key changes and the relatively stable rights management. This intermediary structure allows the system to achieve fast channel switching through traffic key updates without requiring proportional increases in service key update frequency.
Data Source
AI summary
The present invention provides methods, apparatuses, and systems for delivering protected streaming content to a receiving device. In an aspect of the present invention, a broadcaster provides streaming content. To ensure viewers are properly authorized, the streaming content is encrypted with a traffic key. The traffic key is provided to the users via a key stream message, which is encrypted with a service key. The user obtains at least one rights object from a rights issuers and the at least one rights object includes the service key so that the streaming content may be used. The at least one rights object also contains information regarding usage rights that may be configured by the rights issuer so that, depending on the user and/or the receiving device, different rights may be available. The key stream message may include a program category variable value that indicates the type of content and in conjunction with the rights object, determines what usage rights exist for the streaming content.