DRM Move Cache Prevents Rights Duplication
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Solution Overview
Problem
The OMA DRM system lacks a suitable solution to prevent duplication of digital rights objects during backup and transfer, leading to potential unauthorized use and user experience issues, as users can restore backup rights objects to the original device after moving them to another device, allowing for duplicate rights.
Innovation Solution
Implementing a move cache within the DRM device to store information about transferred rights objects, which checks and rejects the installation of rights objects if they have been previously moved or backed up to prevent duplication, using a cryptographic hash to uniquely identify rights objects and manage cache size by exporting excess data to external storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a backup rights object is copied from the originating device to another medium, then the rights can be restored or reinstalled to the originating device, but the rights object can be duplicated and used on multiple devices
Solution Approach 1:
The system performs preliminary actions by creating a backup rights object and storing it in a designated backup location before any transfer or usage occurs. This allows the rights to be restored if needed while maintaining control over the backup copy's usage.
Solution Approach 2:
A rights issuer serves as an intermediary that verifies and manages rights objects. When a backup rights object is encountered, the rights issuer checks whether it has been transferred and uses this information to prevent unauthorized duplication while allowing legitimate restores.
2Adaptability or versatility
If a rights object is transferred from the source device to another device, then the rights can be exercised on the new device, but the rights object cannot be restored to the original device
Solution Approach 1:
Before transferring a rights object, the system creates a backup copy at the source device and stores it in a backup location. This preliminary backup ensures that the original device can restore its rights if needed, while the transferred rights object can still be used on the new device.
Solution Approach 2:
The system creates a backup rights object that is a copy of the original rights object. This copy is stored in a backup location and can be used to restore the original device's rights without affecting the transferred rights object's functionality on the new device.
3Adaptability or versatility
If both backup and transfer of rights objects are allowed, then user flexibility is improved, but rights duplication and unauthorized use may occur
Solution Approach 1:
The rights issuer receives feedback about transferred rights objects and uses this information to verify backup rights objects. When a backup rights object is encountered, the system checks with the rights issuer to determine if it has been transferred, and this feedback mechanism prevents unauthorized duplication while allowing legitimate operations.
Solution Approach 2:
The rights issuer acts as an intermediary that mediates between the backup rights object and the system. It verifies whether a backup rights object has been transferred and uses this verification to prevent harmful duplication while allowing flexible rights management.
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
The present invention relates to a digital right management device (20), the device comprising a memory area (22) for storing information on a rights object that has been transferred from the DRM device (20) to another DRM device, wherein the rights object comprises permissions linked to a digital media object, and a processor (24) for receiving a rights object, wherein the processor is operative to access the memory area (22) to check whether information on the received rights object is stored in the memory area (22) and to set up the received rights object on the digital right management device (20) in case the information on the received rights object is not stored in the memory area (22) and to reject the received rights object in case the information on the received rights object is stored in the memory area (22).