The OPC UA security model is implemented through the definition of a secure channel, on which a session is based. A secure channel makes the exchange of data secure in different ways:
- It ensures the integrity of the data using digital signatures.
- It ensures confidentiality through encryption.
- It carries out the authentication and authorization of applications using X.509 certificates.
The entities involved, as shown in the following diagram, are the Application Layer, the Session, and the Transport Layer:
- The Application Layer is used to transmit information between clients and servers that have established an OPC UA session.
- An OPC UA session is established on a secure channel (located in the Communication Layer), ...
