Evaluating Decoupled Certificate Management in Modular Automation Architectures through Blockchain-Based Approaches

Modular automation architectures enable flexible, plug-and-play production systems by encapsulating individual control logic within independent modules. However, security mechanisms, and certificate management in particular, conflict with this paradigm because the current centralized design of public-key infrastructures makes it difficult to integrate heterogeneous communication protocols in nested architectures.

This work investigates blockchain-based certificate management as a decentralized alternative for enabling secure and automated trust infrastructures within process modules. Following a structured review of transferable blockchain PKI approaches from the IT domain, a synthesized architecture for operational technology environments is derived, and a proof-of-concept using Hyperledger Fabric with on-chain governance and off-chain threshold-signature operations is implemented. Validation in an industrial automation like environment demonstrates the feasibility of the approach while highlighting key limitations, particularly storage inefficiencies. The results indicate that purely IT-based proposals for blockchain-based certificate management are insufficient, but the proposed reference architecture provides a basis for adoption in industrial automation.