Connections between an OPC UA Server and an OPC UA Client (OPC UA Toolkit)

The LabVIEW OPC UA Toolkit supports both non-secure connections and secure connections between an OPC UA server and an OPC UA client.

In a non-secure connection, the OPC UA server and OPC UA client do not need to trust each other. When the OPC UA server supports a non-secure connection, the OPC UA client can connect to the OPC UA server without security.

In a secure connection, the OPC UA server and OPC UA client must trust each other to protect the data exchange between the OPC UA server and OPC UA client. To establish a secure connection between an OPC UA server and an OPC UA client, you must complete the following tasks:

• Ensure that the OPC UA server supports a secure connection.
• Ensure that the OPC UA server trusts the certificate file that the OPC UA client uses.

• Ensure that the OPC UA client uses the secure message modes and corresponding security policies supported by the OPC UA server.

  A message mode specifies the encryption mode that the OPC UA client uses when the OPC UA server and OPC UA client send messages to each other. The OPC UA Toolkit supports three message mode options: None, Sign, and Sign and Encrypt. A security policy specifies how the OPC UA server and OPC UA client sign and encrypt messages. The OPC UA Toolkit supports Basic128Rsa15 and Basic256 security policy options.

• Ensure that the OPC UA client trusts the certificate file that the OPC UA server uses.