Server Device Content License Binding and Backup
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Solution Overview
Problem
Existing content distribution systems fail to effectively prevent unauthorized use of digital content and do not allow users to back up content to other storage media, leading to inconvenience for users and difficulties for content providers in collecting usage fees.
Innovation Solution
A content distribution system that includes a server device and a playback device, where the server device acquires unique user information, generates binding information, and outputs a converted title key, usage rule, and encrypted content, while the playback device receives this information, performs reverse conversion, decrypts the content, and plays it back, allowing for secure and convenient content usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If content is encrypted and stored in authorized storage medium with medium unique key, then unauthorized copying is prevented, but users cannot back up content to other storage media
Solution Approach 1:
The system separates the content protection mechanism into two independent parts: (1) medium unique key binding to the original storage medium for preventing unauthorized copying, and (2) license information containing decryption key that can be transferred to other storage media for backup purposes. This segmentation allows each function to operate independently without interfering with the other.
Solution Approach 2:
The patent introduces license information as an intermediary element that bridges the gap between content protection and backup functionality. The license information contains the decryption key and can be copied to other storage media, serving as a mediator that enables backup while the medium unique key continues to protect against unauthorized copying on unauthorized media.
2Reliability
If medium unique key is bound to authorized storage medium, then decryption is possible only on authorized medium, but any user can use content on authorized medium making fee collection difficult
Solution Approach 1:
The system divides the authorization mechanism into two separate components: (1) medium unique key that ensures only authorized storage media can decrypt content, and (2) license information that records user identification and usage rights. This segmentation allows the system to track which users have purchased which content through the license information while maintaining strong cryptographic protection through the medium unique key.
Solution Approach 2:
The patent implements a feedback mechanism where the playback device sends usage information (including user identification from license information and content identification) to the content management server. The server tracks and manages usage rights based on this feedback, enabling efficient fee collection and usage monitoring without compromising content protection.
3Ease of operation
If decryption key is stored in license information on storage medium, then content can be decrypted on authorized medium, but copying license information to unauthorized medium enables fraudulent use
Solution Approach 1:
The system separates authorization into two independent layers: (1) medium unique key stored in the authorized storage medium that provides the first layer of security by ensuring only the original medium can initiate decryption, and (2) license information containing decryption key that provides content access control. Both layers must work together for successful decryption, preventing fraudulent use even if license information is copied to unauthorized media.
Solution Approach 2:
The patent implements preliminary verification where the playback device first verifies the medium unique key of the storage medium against the medium unique key recorded in the license information before proceeding with decryption. This preliminary action ensures that even if license information is copied to unauthorized media, the decryption cannot proceed because the medium unique key verification will fail.
Data Source
AI summary
A server device (100a) includes a first generation unit (102a) generating binding information binding a user with content, a second acquisition unit (103a) acquiring a usage rule, a second generation unit (104a) generating a converted title key from a title key by using the binding information and the usage rule, and an output unit (105a) outputting content encrypted using the title key, the converted title key and the usage rule to the storage medium (600a). A playback device (700a) includes a generation unit (704a) performing the reverse of the conversion on the converted title key of the storage medium (600a) to generate a decrypted title key, by using the binding information received from the server device (100a) and the usage rule of the storage medium (600a), and a decryption unit (705a) decrypting the encrypted content of the storage medium (600a) by using the title key.