DMODBUS: Blockchain for Network Identity Validation in Modbus Connections
The Fourth Industrial Revolution, driven by the convergence of Information Technology (IT) and Operational Technology (OT), has accelerated industrial innovation while exposing legacy systems to modern cyber threats. Widely adopted protocols, such as Modbus/TCP, lack native security mechanisms and remain inherently vulnerable to exploitation. This study proposes and validates DModbus, an adaptive security layer that enhances Modbus communications by integrating blockchain technology. The architecture introduces a non-invasive gateway that utilizes a permissioned Proof of Authority (PoA) blockchain as a distributed and immutable ledger for device identities, enabling robust authentication during communication. The proposal was validated through a Proof of Concept (TRL 3) simulating a Man-in-the-Middle (MitM) attack via Address Resolution Protocol (ARP) spoofing in a Modbus TCP/IP environment. The experimental results demonstrate that DModbus detects identity spoofing attempts in real time. Performance analysis quantifies the inherent trade-off: an average latency overhead of 91.3% relative to the unprotected baseline. This overhead suggests suitability for non-critical real-time applications, such as supervisory control and data acquisition (SCADA) systems, rather than high-speed actuators, given the significant gains in security and resilience particularly when contrasted with the severe and unpredictable degradation observed during active attacks. The main contributions are: (i) a model for securing Industry of Things (IIoT) devices using blockchain; (ii) a quantitative assessment of Proof-of-Authority (PoA)-based overhead in OT networks; and (iii) validation of decentralized identity management as a viable security layer for industrial communications.