Central Server Key Management for Secure Content Deciphering
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Solution Overview
Problem
Existing methods for protecting copyrighted audio/video content from excessive copying and transfer between units are inadequate, as they often expose encryption keys during transmission and storage, making them vulnerable to unauthorized access and use.
Innovation Solution
A method where processing units, managed by a central server, use specific keys to generate and manage content keys, ensuring that only authorized units can access and restore encrypted content, by deriving keys from constants and variables provided by the server, and performing ciphering/deciphering operations within chipsets to prevent key exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption keys are transmitted and stored in removable memories for content protection, then content security is improved, but key exposure vulnerability increases
Solution Approach 1:
The patent introduces a central server as an intermediary that manages the encryption keys. Instead of storing keys in removable memories attached to processing units, the server acts as a secure intermediary that issues keys dynamically. This mediator approach eliminates the vulnerability of storing keys in removable memories while maintaining content protection capability.
Solution Approach 2:
The patent segments the key management function from the content storage and processing functions. The central server separately manages keys while processing units handle content operations. This segmentation isolates the sensitive key storage function from the potentially vulnerable removable memory environment, improving security by separating concerns.
2Ease of operation
If specific keys are stored in processing units for content decryption, then authorized access is enabled, but unauthorized copying risk increases
Solution Approach 1:
The central server serves as a mediator that controls key distribution to processing units. The server can issue keys to authorized units while preventing unauthorized copying by controlling key issuance. This intermediary approach enables authorized access through key distribution while mitigating unauthorized copying risks through centralized control.
Solution Approach 2:
The patent implements dynamic key management where keys are issued dynamically by the central server to processing units based on authorization status. Rather than static key storage, the system dynamically manages keys, allowing authorized access while preventing unauthorized copying through dynamic control of key distribution.
3Reliability
If content keys are generated from constants and variables for secure storage, then key confidentiality is improved, but system complexity increases
Solution Approach 1:
The patent uses preliminary action by pre-establishing constants that are provided by the central server before key generation. These constants serve as pre-computed values that simplify the key generation process while maintaining security. The constants are prepared in advance and used during content key generation, reducing the complexity burden during actual operation.
Solution Approach 2:
The patent changes parameters in the key generation process by using constants and variables provided by the central server. Instead of generating keys from scratch with complex algorithms, the system uses parameter changes (deciphering constants and variables) to derive content keys. This approach maintains key confidentiality while simplifying the generation process through parameter-based derivation.
Data Source
AI summary
A method of operating by a second processing unit a content recorded by a first processing unit, said first and second processing units having a specific key being managed by a central server. The processing units have access to a removable storage memory intended to record a content ciphered by a content key accompanied by a file associated to the content. The content key is produced by means of a cascaded deciphering starting from the specific key of the first unit of at least two constants provided by the central server and a variable. The content is restored by the second processing unit by means of a cascaded deciphering starting from the specific key of the second unit by using the constants and the variable stored in the file accompanying the content and a transcoding key calculated by the central server.