TRUST Issues: Multicast and Integrity Protection for the TRUST Redundancy Mechanism

The continued integration of industrial control systems in many critical infrastructures demands an increased focus on reliability and security. Low latency redundancy mechanisms are used to increase communication reliability (e.g. PRP, HSR). While protection against cyber attacks receives continued focus, the security of such lower layer mechanisms seems to be overlooked. Such mechanisms can introduce new attack vectors, that can not be combatted with end-to-end cryptography on higher layers. The TRUST redundancy mechanism presents an alternative approach to packet redundancy, that is not susceptible to similar attacks. In this paper, the use of TRUST to increase the reliability of multicast communication in LAN and WAN networks is presented. Specifically, we consider the interaction with multicast group management protocols in LAN and WAN and present example deployments. We also propose an optional integrity protection mechanism that further strengthens TRUST's resilience against attacks. With these new features, TRUST can support additional use cases. We discuss such use cases in the context of the smart grid.