Hierarchical Encryption Key System for Secure Media Delivery
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Solution Overview
Problem
Existing cable and satellite content distribution networks face challenges in securely delivering digital media content that supports both broadcast and delayed or time-shifted modes, as they rely on a single layer of encryption keys, making them vulnerable to hacking and unable to efficiently manage both delivery modes.
Innovation Solution
The hierarchical encryption key system employs multiple encryption processes with a hierarchical series of keys, where some keys are transmitted in-band and others out-of-band, and aggregates keys for secure storage and playback, making it difficult to use brute force attacks and balancing frequent key changes with key separation for stronger security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single layer of encryption keys is used, then the system is simpler to implement, but security is weakened and both broadcast and delayed content delivery modes cannot be supported
Solution Approach 1:
The encryption key structure is segmented into multiple hierarchical layers (first encryption layer, second encryption layer, third encryption layer) with different key types (content keys, section keys, master keys). Each layer handles specific encryption tasks for different content delivery modes, resolving the contradiction by dividing the monolithic key system into functional segments that provide both security and versatility.
Solution Approach 2:
The system transitions from a single-dimensional key structure to a multi-dimensional hierarchical key structure with three distinct layers. This dimensional expansion allows the system to simultaneously support broadcast mode (using content keys), delayed content delivery (using section keys), and key management (using master keys), thereby achieving both security and mode flexibility without excessive complexity.
2Ease of operation
If a single layer of encryption keys is used, then the system is easier to manage, but it cannot securely support both broadcast and delayed content delivery modes
Solution Approach 1:
The key management function is segmented across three hierarchical layers, with each layer managing specific aspects: content keys for broadcast decryption, section keys for delayed content sections, and master keys for key distribution. This segmentation enables the system to handle multiple delivery modes while maintaining manageable operational complexity through clear functional division.
Solution Approach 2:
The hierarchical key structure provides multi-functionality where the same system architecture serves multiple purposes: the first layer handles broadcast content decryption, the second layer manages delayed content delivery, and the third layer handles key distribution and management. This universal design allows a single system to adapt to different content delivery requirements without requiring separate key management systems for each mode.
3Ease of operation
If encryption keys are transmitted in-band, then key delivery is simpler, but security is compromised due to exposure to hacking attempts
Solution Approach 1:
The key transmission process is segmented into two distinct channels: in-band transmission for content data and out-of-band transmission for encryption keys. Critical keys (master keys and section keys) are transmitted out-of-band through separate secure channels to avoid exposure to hacking attempts, while content keys are transmitted in-band with the content stream. This segmentation resolves the contradiction by separating transmission functions.
Solution Approach 2:
The patent introduces out-of-band transmission channels as intermediaries for delivering critical encryption keys. These intermediary channels act as secure conduits that separate key delivery from content transmission, preventing direct exposure of keys to hacking attempts while maintaining efficient key delivery. The intermediary channel layer provides an additional security dimension without complicating the overall system.
Data Source
AI summary
The hierarchical encryption key system uses multiple encryption processes for encrypting digital media content in a manner that supports both broadcast and delayed or time-shifted modes of content delivery. The hierarchical encryption key system uses a hierarchical series of encryption keys wherein each subsequent key in the hierarchy encrypts successively increasing time periods of the content that is transmitted from the Cable Modem Termination System to the consumer device. In addition, at one of the layers, the keys are aggregated into a collection or table of keys. The aggregation of keys facilitates the playback of recorded digital content (as opposed to broadcast or streaming digital content) by aggregating keys required for the duration of the content separately. The different layers are linked in a manner to make it difficult to use a brute force attack in an attempt to determine the keys.