Topic-Based Key Derivation for Secure Publish-Subscribe Systems
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Solution Overview
Problem
Existing topic-based publish-subscribe systems face challenges in providing end-to-end security and efficient key management for decentralized IoT and industrial networks, particularly in ensuring secure communication and limiting access to specific communication groups.
Innovation Solution
A method involving a key distribution server that provides a group key to local client systems, allowing for local derivation of subgroup keys based on specific topics, ensuring cryptographic protection and authentication within subgroups, and enabling hierarchical key distribution to limit misuse and enforce access control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a central key distribution server is used to provide group keys to all client systems, then key management is simplified and centralized, but security is compromised because compromise of the group key affects all client systems and topics
Solution Approach 1:
The patent segments the single group key into multiple topic-specific subgroup keys. Each client system derives a unique subgroup key for each topic it subscribes to using a key derivation function with the group key and topic identifier as inputs. This segmentation ensures that compromise of one subgroup key does not affect other topics or client systems, while maintaining centralized key distribution through the key distribution server.
2Productivity
If the same group key is used for all communication topics, then key distribution is efficient and simple, but access control precision is reduced as all clients can access all topics
Solution Approach 1:
The patent applies local quality by making cryptographic keys topic-specific rather than universal. Each client system possesses the same group key from the key distribution server, but locally derives different subgroup keys for different topics using the key derivation function. This allows precise access control where each client only has cryptographic access to topics it is authorized for, while maintaining efficient centralized key distribution.
3Reliability
If hierarchical key derivation is implemented for subgroups, then access control is improved and misuse is limited, but key derivation complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-distributing the group key to all authorized client systems through the key distribution server before any topic-specific communication occurs. Each client system then autonomously performs key derivation locally using the pre-distributed group key and topic identifiers. This preliminary distribution simplifies the overall system architecture while enabling fine-grained access control through local key derivation operations.
Data Source
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AI summary
The invention relates to a method for transferring data in a topic-based publish-subscribe system, comprising a key distribution server and a number of local client systems that can be coupled to the key distribution server, comprising: providing a group key by means of the key distribution server for a group selected from the local client systems, locally deriving a first-order sub-group key for a first-order sub-group of the group by means of key derivation parameters at least comprising the provided group key and a certain topic of the publish-subscribe system by means of the particular client system of the first-order sub-group, and transferring at least one message cryptographically protected by means of the derived first-order sub-group key between the client systems of the first-order sub-group. Differentiation within group communication according to topic by means of specific cryptographic keys is thereby enabled. The invention further relates to a device for transferring data in a publish-subscribe system and to a publish-subscribe system.