OPC UA.

OPC Unified Architecture, a service-oriented industrial protocol with built-in authentication and encryption used to exchange semantic data across OT and IT systems. It belongs to the OT / ICS / IoT category of cybersecurity.

OPC Unified Architecture, a service-oriented industrial protocol with built-in authentication and encryption used to exchange semantic data across OT and IT systems.

OPC UA (Unified Architecture, IEC 62541) is the modern successor of classic OPC and the dominant secure interoperability standard in industrial automation. It exposes a semantic, object-oriented information model and supports both client-server and pub-sub interactions over TCP, HTTPS, or MQTT, making it suitable for everything from field-level devices to cloud analytics. Unlike Modbus or DNP3, OPC UA includes X.509 certificate-based authentication, role-based authorization, message signing, and AES encryption by default. Misconfigurations remain a risk: anonymous endpoints, weak certificate validation, exposed discovery services, and outdated stacks have been exploited in penetration tests and real attacks, so secure deployment requires a strong PKI and explicit security policies.

Defences for OPC UA typically combine technical controls and operational practices, as detailed in the full definition above.

Common alternative names include: OPC Unified Architecture, IEC 62541.