1. A system, comprising: a controller, comprising: a data repository configured to store a first mapping associating a user to an application certificate and a second mapping associating the user to a user privilege; and an Object Linking and Embedding (OLE) for Process Control (OPC) Unified Architecture (UA) server configured to provide server access based on receiving the application certificate from an OPC UA client and enforcing the user privilege, wherein the user privilege is retrievable based on the first and the second mappings.