Capability Revocation in Content Consumption Devices
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Solution Overview
Problem
Existing methods for managing the capability of devices to process and display content remotely are difficult to maintain and enforce, particularly in scenarios where devices have been compromised, as revocation lists are challenging to manage and enforce effectively.
Innovation Solution
A method involving the use of capability verification information and decryption keys, where the revocation list is cryptographically bound with the decryption key, ensuring that devices can only access content if their capabilities have not been revoked, and the revocation list is up-to-date, thereby enabling granular control and enhanced enforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a revocation list is distributed to identify devices to be revoked, then device capability management is enabled, but the system becomes difficult to maintain and enforce
Solution Approach 1:
The patent combines the revocation list with the activation message into a single integrated structure. The revocation list is not distributed separately but is embedded within the activation message that the device receives anyway, eliminating the need for separate revocation list distribution and maintenance mechanisms.
Solution Approach 2:
The revocation list is provided in advance within the activation message before the device attempts to access content. This preliminary provision of revocation information allows the device to perform capability verification before content decryption, preventing unauthorized access without requiring ongoing revocation list updates or separate verification processes.
2Object-affected harmful factors
If revocation lists are used to control device capabilities, then content security is improved, but the ease of operation deteriorates
Solution Approach 1:
The device autonomously performs capability verification by comparing its own capabilities against the revocation list provided in the activation message. The device independently determines whether it should access content based on the revocation information, without requiring external intervention or complex manual verification processes.
Solution Approach 2:
The revocation list is provided in advance within the activation message before the device attempts to access content. This preliminary provision of revocation information allows the device to perform capability verification before content decryption, preventing unauthorized access without requiring ongoing revocation list updates or separate verification processes.
3Measurement precision
If granular control of individual capabilities is implemented, then access control precision is improved, but the system complexity increases
Solution Approach 1:
The patent segments capabilities into distinct types (e.g., decryption capability, display capability, processing capability) and provides granular revocation control for each capability type. The revocation list can specify which particular capabilities are revoked for a device, allowing precise control over access rights at the capability level rather than treating all capabilities uniformly.
Data Source
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Figure 3A~3B
AI summary
Methods and content consumption devices are disclosed that enable a revocation list to be securely enforced and managed, in terms of enforcing version control and providing granular control of individual capabilities, for example. Aspects also relate to enhanced enforcement control of content consumption control information more generally, for example by enforcing version control of activation messages, and/or granular management of individual capabilities.