Next-generation industrial networks incorporate diverse devices and technologies, including cloud- and fog-based systems and large-scale Industrial Internet of Things (IIoT) applications. These heterogeneous environments comprise thousands of sensors, actuators, controllers, and geographically distributed zones, posing significant challenges for authentication mechanisms that must scale while remaining secure and practical under real industrial conditions. Current blockchain-based decentralized identity-management systems are characterized by high transaction overhead, reliance on computationally intensive cryptographic operations, and partial dependence on trusted entities, all of which limit their scalability and practical deployment. To address these issues, in this paper, we propose a lightweight, blockchain-based identity-management solution that integrates epoch- and batch-based registration with sparse Merkle trees (SMTs). Device registrations are grouped into fixed epochs, and cryptographic costs are amortized across multiple devices to substantially reduce per-device overhead. The SMT structure generates verifiable, reusable proofs that preserve privacy while enabling efficient verification; sensitive device information is never revealed during authentication. Fog nodes act as decentralized verifiers, supporting distributed trust without continuous interaction with the blockchain. Experimental results show that the system can be practically deployed on Raspberry Pi and ESP32 devices, reliably perform identification with around 1000 total messages, and operate at the tested upper bound of 7000 devices distributed over 20 fog nodes, all while keeping the blockchain storage overhead under 5 MB.

Next-generation industrial networks are designed to integrate a wide range of devices, services, and applications spanning multiple technologies, such as cloud platforms, edge computing, and the Internet of Things. With the growing adoption of applications such as “Industry 4.0,” high security and low latency are becoming unavoidable requirements for these networks. Traditional virtual private networks (VPNs) generally experience performance, latency, and security issues, especially when supporting secure remote access for Industry 4.0 and ehealth applications. To address these issues, this study introduces a novel zero-trust network-access framework for next-generation industrial networks called Secure Transmission (SecT). SecT is a User Datagram Protocol (UDP)-based solution, ensuring speed and effectiveness, with role-based access control. It uses a centralized management interface that can adapt to various network environments, providing secure access to mission-critical applications and increasing operational agility. SecT aims to meet the emerging demands of modern industrial networks, offering secure access with improved performance. The results of a comparative analysis show that SecT outperforms traditional VPNs in both capability and flexibility, adapting well to new network conditions.