Secure Data Relay in Federated Digital Twins of IoT-enabled Smart Interconnected Factories

Smart interconnected factories allow manufacturing units from physically distanced factory sites to communicate classified information needed for additive manufacturing. Each factory has interconnected digital twins of their equipment autonomously managed by a Point-of-Contact digital twin creating a hierarchical system with federated digital twins. The data sharing between the factories must be directed through an edge node responsible for managing multiple factories. We proposed a novel lightweight protocol to prevent the leakage of classified information at any nodes other than the origin and destination digital twins. It leverages elliptic curve cryptography to design a proxy re-encryption scheme with the edge node as the proxy. Informal security analysis of our proxy invisible and key optimal protocol reveals security against chosen plaintext attacks, chosen ciphertext attacks, and ciphertext injection attacks. Implementation in Python and cost analysis reveal that our protocol is lightweight in computation, communication and storage costs.