Cross-Compatible Encryption Adapter for Securing Legacy Modbus Devices

Supervisory Control and Data Acquisition systems are the backbone of managing critical infrastructure in modern industrial control systems, spanning sectors from power generation to logistics. However, these systems face significant challenges due to threats from malicious actors. The Modbus protocol, despite its known lack of security features, is still used in many industries managing critical infrastructure due to the high cost of replacing existing systems. As a result, these legacy systems remain vulnerable to potentially damaging threats. This paper proposes an adapter device for enhancing the security of the Modbus protocol without replacing devices in legacy systems. The proposed adapter is cost-efficient, provides cross-platform support, and is easy to install, update, and maintain.