Cryptographic Entity Group Segmentation for Secure Key Diversification
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Solution Overview
Problem
Existing multimedia signal reception systems struggle to restrict a first cryptographic entity to only work with a specific group of second entities, while maintaining security and adaptability across different protection modes.
Innovation Solution
Implementing a method where only a group of N second entities, chosen from a larger set of P entities, use a session key derived from a common root key, ensuring the first entity is usable only within this group by rendering the diversification module unusable after connection, and using security integrated circuits to store and decrypt session keys securely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a first cryptographic entity is designed to work with any second entity using a common root key, then universality and ease of operation are improved, but security is worsened because the first entity cannot be restricted to a specific group of second entities
Solution Approach 1:
The system segments the set of second entities into multiple groups, each group associated with a specific root key. The first cryptographic entity is configured to work only with second entities from its assigned group, creating segmented access control that maintains security while preserving universality within the designated group.
Solution Approach 2:
Each first cryptographic entity is assigned specific local qualities through configuration parameters that identify its authorized group of second entities. This local quality approach allows the entity to maintain universality within its designated scope while being restricted from other groups, resolving the contradiction between broad adaptability and security constraints.
2Reliability
If a first cryptographic entity is restricted to work only with a specific group of N second entities, then security is improved, but adaptability is worsened because the entity cannot be used with other second entities
Solution Approach 1:
The first cryptographic entity maintains multi-functionality by being able to work with any second entity within its designated group of N entities. While restricted from other groups, it achieves universality within its scope, allowing it to serve multiple purposes and compatible devices without requiring multiple specialized entities.
Solution Approach 2:
The system uses parameter changes in the form of group identification parameters and root key selections to enable the first entity to adapt its operation to different second entities within its authorized group. This parameter-based approach maintains security restrictions while providing flexibility and adaptability within the permitted scope.
3Ease of operation
If session keys are obtained by diversifying root keys using the same identifier, then ease of operation is improved through automatic key matching, but security is worsened because the diversification module remains usable for creating new session keys
Solution Approach 1:
The system performs preliminary action by rendering the diversification module unusable immediately after the first and second entities are connected and have established their session key. This preliminary security measure prevents any subsequent unauthorized key generation while maintaining the ease of automatic key matching during the legitimate connection process.
Solution Approach 2:
The system extracts the diversification capability from the first cryptographic entity after use, effectively removing the ability to create new session keys once the connection is established. This extraction of the key generation function maintains security by preventing unauthorized key creation while preserving the automatic matching functionality during the legitimate pairing process.
Data Source
AI summary
This method of receiving a multimedia signal scrambled by means of a control word uses a first cryptographic entity that can be connected to any one of P second cryptographic entities to form part of a device for receiving the scrambled multimedia signal. Only second cryptographic entities of a group of N second cryptographic entities selected from a wider set of P second cryptographic entities use a session key obtained by diversifying a root key identical to the root key used to obtain the session key of the first cryptographic entity.