Blu-ray Client Authentication via AACS Cryptographic Permissions
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Solution Overview
Problem
The Advanced Access Content System (AACS) does not provide explicit mechanisms for content providers to reliably authenticate client applications executing on AACS-compliant devices, making it difficult to distinguish between authorized and unauthorized clients, especially in networked environments, which can lead to unauthorized access to protected content.
Innovation Solution
The implementation of cryptographic authentication techniques using AACS elements, such as the AACS Layer API, to validate client applications by generating and verifying AACS Permissions, ensuring that only non-revoked AACS-compliant devices can access encrypted content, and using a mechanism like bogus authentication permissions to authenticate clients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AACS content protection system is implemented to protect against unauthorized access to copyrighted content, then content security is improved, but the system lacks explicit mechanisms for client authentication, making it difficult to distinguish between authorized and unauthorized clients
Solution Approach 1:
The patent introduces an intermediary authentication mechanism that mediates between the AACS content protection system and the client application. This intermediary layer uses cryptographic permissions and proofs to verify client authenticity without requiring fundamental changes to the AACS protocol, thus resolving the contradiction between maintaining content security and implementing authentication without increasing system complexity
2Reliability
If cryptographic authentication mechanisms are added to authenticate clients in networked environments, then client authentication reliability is improved, but the system complexity and implementation difficulty increase
Solution Approach 1:
The patent applies preliminary action by pre-generating cryptographic permissions and proofs that can be verified without complex real-time authentication infrastructure. The client application creates cryptographic proofs beforehand using the AACS permission, allowing the server to authenticate clients through simple verification of these pre-computed credentials, thus improving authentication reliability while minimizing system complexity
3Reliability
If AACS permission validation is used to authenticate client applications, then unauthorized access prevention is improved, but the difficulty of detecting and measuring client authenticity increases
Solution Approach 1:
The patent replaces mechanical or procedural authentication methods with cryptographic verification. Instead of relying on complex validation procedures to detect client authenticity, the system uses cryptographic proofs and permissions that can be automatically verified through mathematical validation, thus improving unauthorized access prevention while reducing the difficulty of detecting client authenticity
Data Source
AI summary
Techniques are described herein for using cryptographic elements of the Advanced Access Content System (AACS) in a client-server environment to cryptographically authenticate client applications that are executing on non-revoked AACS-compliant playback devices. The techniques described herein may be used to protect a server application from providing information to client applications executing in non-AACS-compliant or revoked environments. In one embodiment, the techniques are used to authenticate a Blu-ray Disc Java Application executing on a non-revoked AACS-compliant Blu-ray Disc Player.