Hierarchical Key Management for DRM Scalability
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Solution Overview
Problem
Conventional digital rights management (DRM) systems face security inadequacies due to the use of static content decryption keys, which can be compromised and distributed illegally, and scalability issues, particularly in Pay-Per-View broadcasts, where public key cryptography is too slow and requires expensive hardware.
Innovation Solution
A cryptographic key management system with multiple layers, including a public/private key pair and three additional symmetric keys, to minimize bandwidth usage and enhance security, allowing for frequent updates of content decryption keys and efficient handling of large user bases without the need for expensive hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static content decryption key is delivered to each receiver using public key cryptography, then security is provided for content access, but the same key can be compromised and illegally distributed, creating infinite scope security breaches
Solution Approach 1:
The patent transforms the static content decryption key into a dynamic key that changes frequently. Instead of delivering the same key repeatedly, the system generates new content decryption keys for each content delivery or time period, making compromise less valuable to attackers and eliminating the infinite scope security breach problem.
Solution Approach 2:
The patent segments the key management into multiple hierarchical levels: master keys, session keys, and content-specific decryption keys. This segmentation allows the system to revoke or update individual content keys without affecting the entire system, limiting the scope of any potential compromise.
2Reliability
If public key cryptography is used to deliver content decryption keys to each user, then security is maintained, but the system is too slow and requires expensive hardware for large-scale broadcasts
Solution Approach 1:
The patent divides key delivery into two segments: a one-time public key exchange for establishing trust, followed by efficient symmetric key distribution for actual content decryption. This segmentation allows the system to maintain security through public key cryptography while achieving fast key delivery through symmetric encryption for the bulk of content distribution.
Solution Approach 2:
The patent introduces session keys as intermediaries between the master key and content decryption keys. These session keys are distributed efficiently to multiple receivers and then used to derive individual content-specific keys, reducing the computational burden on each receiver and enabling scalable key management without expensive hardware accelerators.
3Device complexity
If a static content decryption key is used for a single piece of content, then key management is simplified, but bandwidth usage increases when the same key must be securely distributed to multiple receivers
Solution Approach 1:
The patent creates session keys that serve multiple functions: they authenticate receivers, encrypt content delivery, and derive individual content decryption keys. This multi-functionality reduces the number of separate key management operations needed and minimizes bandwidth usage by consolidating multiple security functions into a single key exchange process.
Data Source
AI summary
Described herein are embodiments that provide an approach to cryptographic key management for a digital rights management (DRM) architecture that includes multiple levels of key management for minimizing bandwidth usage while maximizing security for the DRM architecture. In one embodiment, there is provided a data structure for cryptographic key management that includes a public/private key pair and three additional layers of symmetric keys for authorizing access to a plurality of contents.