Secure Module Key Ladder for Multi-Provider Content
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Solution Overview
Problem
Conventional content protection systems require users to obtain new devices when switching between content providers, limiting flexibility and increasing costs for both users and providers, as proprietary devices are typically used for each service.
Innovation Solution
A device with a secure module capable of installing provider-specific client software modules, using link keys for authentication and decryption, allowing secure download and installation of software images, and enabling decryption of protected content for playback across multiple providers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If proprietary user devices are used for each content provider, then security level is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a universal user device that can serve multiple content providers through a common interface framework. The device includes a secure module with a key ladder mechanism that allows it to securely install and execute client software modules from different providers without compromising security. This multi-functional capability eliminates the need for separate proprietary devices for each provider while maintaining high security standards through cryptographic protection of decryption information.
2Reliability
If proprietary user devices are used for each content provider, then security level is improved, but loss of substance increases
Solution Approach 1:
The universal device architecture allows a single device to replace multiple proprietary devices, reducing hardware costs for both users and content providers. The secure module with key ladder enables multiple content providers to operate on the same device infrastructure, eliminating redundant device manufacturing and distribution costs while maintaining security through cryptographic key management.
3Adaptability or versatility
If a single device supports multiple content providers, then adaptability is improved, but security risks increase
Solution Approach 1:
The patent segments the device into distinct functional components: a secure module for cryptographic operations, a key ladder for hierarchical key management, and separate client software modules for different content providers. Each provider's decryption information is isolated within the secure module, preventing interference between providers while allowing the device to support multiple services simultaneously.
Solution Approach 2:
The key ladder acts as an intermediary mechanism between the secure module and client software modules. It provides a structured approach to key hierarchy where roots keys are protected in the secure module and derived keys are distributed to client modules, enabling secure communication between multiple providers and the device without direct exposure of sensitive cryptographic material.
4Adaptability or versatility
If client software modules are installed from untrusted sources, then adaptability is improved, but harmful factors increase
Solution Approach 1:
The patent implements preliminary authentication of client software modules before installation. The secure module verifies the authenticity and integrity of downloaded modules using cryptographic signatures and the key ladder mechanism. Only authenticated modules are permitted to install and execute, preventing malicious software from compromising the device while maintaining the ability to install from various trusted sources.
Data Source
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AI summary
The invention relates to a device for decrypting protected content and for providing the decrypted content for playback, the device comprising a secure module for carrying out cryptographic operations including the decryption of the protected content using decryption information, and the device being configured to install therein at least one client software module assigned to a provider of protected content, the client software module being adapted to forward decryption information for decrypting the protected content of the provider to the secure module in an encrypted form. The secure module is adapted to store therein a public key assigned to the provider and to authenticate at least one link key provided by the content provider using the stored public key. Further, the secure module is adapted to receive a protected software image of the client software module and to initiate the installation of the client software module in the device upon having decrypted and/or validated the software image by means of a link key authenticated using the registered public key or by means of a key of a key ladder derived from the authenticated link key, and, during execution of the installed client software module, the secure module is adapted to decrypt the decryption information by means of a link key authenticated using the registered public key or by means of key of a key ladder derived from the authenticated link key. Moreover, the invention relates to a method for operating the device.