Each OPC UA application on a device corresponds to a GTA API identifier and at least one personality set. An OPC UA application may use multiple identity personalities corresponding to multiple SecurityPolicies.

Subsection 4.3.2 introduces conventions to be used for GTA API identifiers and personality names being used by OPC UA applications.

The personality’s application property and personality attributes can be used to provide additional distinguishing features depending on the actual personality type. Subsections 4.3.3, 4.3.4, and 4.3.5 provide an in-depth description for three types of personality sets which are commonly used in OPC UA:

• DeviceIdentity Personality set: The personalities representing the DeviceIdentity and corresponding to DeviceIdentity certificates available for the onboarding process. DeviceIdentity Personalities are provided by the device vendor and can be used by OPC UA but are not managed by OPC UA.
• DCA Personality set: The personalities representing the DCA and corresponding to the DCA certificate(s) and the corresponding Trust List.
• Application Instance Personality set(s): Any other personality representing an OPC UA Application Instance corresponding to an Application Instance certificate(s) and the corresponding Trust List.