Segmented Content Encryption for Scalable CDN Delivery
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Solution Overview
Problem
Existing content distribution networks face inefficiencies in encrypting media content, particularly in large networks where encrypting signals just prior to transmission is not scalable, and pre-encrypting content can be inflexible and computationally demanding, requiring periodic re-encryption due to key compromises.
Innovation Solution
Implementing a segmented content encryption system where a local site within the network, such as a headend, encrypts media content into segments, caching both encrypted and unencrypted portions with metadata, and transmitting these segments to consumer devices, reducing the burden on hubs and improving scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If content is pre-encrypted at a centralized location for distribution, then security is improved, but device complexity and computational demand increase significantly
Solution Approach 1:
The patent divides the content distribution network into multiple hierarchical levels (national site, regional sites, local sites, hubs) and segments the encryption function to be performed at distributed local sites rather than centralized. Each local site encrypts content independently using its own key, breaking the monolithic encryption system into smaller, manageable segments that reduce overall device complexity while maintaining security.
2Adaptability or versatility
If encryption is performed at each hub just prior to transmission, then adaptability is improved, but productivity decreases due to inefficiency in large networks
Solution Approach 1:
The patent performs encryption at local sites in advance of distribution to multiple hubs, rather than waiting until the last moment at each hub. This preliminary encryption action allows pre-encrypted content to be distributed efficiently to multiple hubs simultaneously, improving productivity while maintaining the flexibility to use different keys at different levels through the hierarchical key management system.
3Reliability
If periodic re-encryption is performed in response to key compromise, then reliability is maintained, but loss of time increases due to re-encryption requirements
Solution Approach 1:
The hierarchical key structure segments the encryption keys into different levels (national site key, regional site keys, local site keys). If a key is compromised at one level, only the content encrypted with that specific key needs re-encryption, not all content in the entire network. This segmentation limits the scope of re-encryption operations, reducing time loss while maintaining security.
4Device complexity
If content is encrypted with a single key throughout the distribution network, then device complexity is reduced, but adaptability decreases when key compromise occurs
Solution Approach 1:
The patent introduces a hierarchical dimension to key management, organizing keys in a tree structure with multiple levels (national site, regional sites, local sites) rather than using a single flat key. This dimensional change allows the system to maintain relatively simple key management at each level while gaining the adaptability to respond selectively to key compromises by affecting only the affected branch of the hierarchy.
Data Source
AI summary
Techniques for encrypting content in a content distribution network are disclosed. The content distribution network may comprise a number of national and local sites, and a number of hubs at each local sites. A content segment encrypting device may be operative at a local site to encrypt and cache segments of content. The segment encrypting device may provide the segments to streaming devices that encode content for delivery downstream to network or user devices.