DRM Rights Object Backup Format Segmentation
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Solution Overview
Problem
Current digital rights management (DRM) systems, such as the OMA DRM family, lack a standardized format for backing up rights objects, leading to vendor-specific implementations that complicate user management, security, and the inability to restore backed-up rights objects across devices.
Innovation Solution
A common backup format is introduced that separates non-critical and critical information within a digital rights object, encrypting critical information with a device-specific key and signing it with the originating device's private key, allowing for secure storage and restoration across devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vendor-specific backup formats are used for DRM rights objects, then implementation flexibility is improved, but interoperability and user management capability deteriorate
Solution Approach 1:
The backup rights object is segmented into distinct components: a header portion containing format identification and metadata, and a payload portion containing the encrypted rights object. This segmentation allows different vendors to implement their own encryption and protection mechanisms in the payload while maintaining a standardized header structure that enables interoperability and universal recognition of the backup format.
Solution Approach 2:
The backup rights object structure is designed to be universal by incorporating a standardized header that can be recognized and processed by any DRM-compliant device. The header contains essential information such as format version, device binding identifier, and rights object metadata that enables any compliant system to understand and restore the backup, while the payload can accommodate vendor-specific implementations.
2Reliability
If rights objects are backed up in a protected form without specification, then security is improved, but usability and trackability deteriorate
Solution Approach 1:
The rights object is encrypted and bound to the originating device's identifier before the backup process occurs. This preliminary cryptographic binding ensures that the rights object remains secure and can only be restored to the original device, while the header contains pre-computed metadata that enables easy identification and tracking of the backup without requiring decryption first.
Solution Approach 2:
A standardized header structure acts as an intermediary between the encrypted payload and the user/device. The header contains readable metadata about the backed-up rights object (such as content description, rights information, and device binding) that allows users to identify and manage their backups without needing to decrypt or understand the protected payload, thus improving usability while maintaining security.
3Reliability
If manual tracking of rights objects is required, then security control is improved, but time consumption and complexity deteriorate
Solution Approach 1:
The backup rights object structure includes self-describing metadata in the header that automatically identifies the originating device, the type of rights object, and other relevant information. When a device needs to restore a backup, it can automatically match the backup to itself using the device binding identifier in the header without requiring manual intervention or external tracking systems, thus reducing time consumption while maintaining security control.
4Reliability
If proprietary backup formats are used for each vendor, then device-specific security is improved, but general tool development and cross-vendor compatibility deteriorate
Solution Approach 1:
The backup format is segmented into a standardized header and a vendor-specific payload. The header contains universal metadata and format information that enables general-purpose tools to read, validate, and manage backups from any vendor. The payload contains the actual encrypted rights object that can be processed by vendor-specific restoration routines, thus reducing overall system complexity while maintaining device-specific security.
Solution Approach 2:
Different parts of the backup structure have different quality requirements: the header portion is standardized with uniform structure and encoding for universal compatibility, while the payload portion allows vendor-specific encryption methods and formats. This local quality differentiation enables general tools to operate on the standardized header while vendor-specific security measures are applied only where needed in the payload.
Data Source
AI summary
A common backup format of a backup rights object according to embodiments of the present invention has the following features: License information that is not critical for cryptographic security of the rights object is kept in “plain text” with a well defined syntax in a first data container, license information that is critical for cryptographic security of the rights object is stored in cryptographically protected form that is specific for the originating device to which the rights object is bound to in a second data container, and the rights object is cryptographically signed by the originating device such that it may not be manipulated. The signature is stored in a third data container.