Message security in PubSub concerns integrity and confidentiality of the published message payload. The base concepts for OPC UA security are defined in OPC 10000-2. The level of security can be:
- No security
- Signing but no encryption
- Signing and encryption Message security is end-to-end security (from Publisher to Subscriber) and requires common knowledge of the cryptographic keys necessary to sign and encrypt on the Publisher side as well as validate signature and decrypt on the Subscriber side.
The keys used for message security are managed in the context of a SecurityGroup. The basic concepts of a SecurityGroup are described in 5.3.7.
This standard defines a general distribution framework for cryptographic keys. This framework is introduced in 5.4.4.
All parameters that are relevant for message security are described in 6.2.5. These parameters are independent of any Broker level transport security.
The message security for PubSub is independent of the transport protocol mapping and is completely defined by OPC UA.