Broadcast Encryption Key Descriptors Using Subset Difference Trees
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Solution Overview
Problem
In broadcast encryption systems, the size of key allocation descriptors grows with additional devices and revocations, making them inefficient for storage and transmission, and complicating the separation of key allocation and generation processes across multiple computers.
Innovation Solution
The use of a subset difference tree approach and media key block descriptors that include variant data pointers to reduce descriptor size, allowing for space-efficient key allocation and generation, with techniques such as duplicate subset elimination and random value encoding to minimize storage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional key allocation descriptors are used in broadcast encryption systems, then complete key management coverage is achieved, but descriptor size grows excessively large with additional devices and revocations
Solution Approach 1:
The key allocation descriptor is segmented into multiple components: subset definitions, variant definitions, and pointers. Instead of storing complete key allocation information for all devices in a single large structure, the system divides the descriptor into manageable segments that can be efficiently stored and processed, reducing overall descriptor size while maintaining complete key management coverage
Solution Approach 2:
The patent introduces a new dimensional approach by adding variant definitions and pointer mechanisms to the traditional descriptor structure. This multi-dimensional organization allows the system to reference key allocation information indirectly through pointers and variants, rather than storing all information explicitly, thereby reducing descriptor size from gigabytes to megabytes while preserving adaptability for device additions and revocations
2Quantity of substance
If descriptor size is reduced for efficient storage and transmission, then space efficiency is improved, but the ability to separate key allocation and generation processes across multiple computers is compromised
Solution Approach 1:
The descriptor is segmented into distinct functional components (subset definitions, variant definitions, pointers) that can be independently generated and processed. This segmentation enables different computers to handle different segments of the key allocation process, allowing process separation while maintaining a compact overall descriptor structure that is efficient for storage and transmission
Solution Approach 2:
The patent introduces pointers and variant definitions as intermediary elements that connect different parts of the key allocation process. These intermediaries enable multiple computers to work on different portions of key allocation independently, then combine their results through the pointer-based structure, facilitating process separation across distributed systems while keeping the final descriptor compact
Data Source
AI summary
Space-efficient methods of defining a key allocation scheme within a broadcast encryption system are provided. In some embodiments, a descriptor is received. The descriptor includes a plurality of subset definitions and a plurality of pointers. A data segment is resolved from each of the plurality of pointers. The resulting data segments are assembled into a plurality of variant definitions. A media key block is generated from the plurality of subset definitions and the plurality of variant definitions.