[dwviel]

Yes, I agree that TLS provides replay protection on a suitably reliable network. Don’t know about DTLS or QUIC but I will look further into these. We didn’t really look to much at TCP and TLS, etc. because early on we made design decisions to have components adopt an autonomous posture and work with unreliable networks, as can often be the case for controls. That led us to reject all connection based network protocols such as TCP to avoid the coupling it creates, and to create a very simple, one step protocol for robustness and simplicity. But, I can see where use of TCP and TLS could be useful, even for us, in some cases. To some extent this is a design philosophy that is biased towards simplicity. I’ve noticed that in the software industry there is a bias towards complexity. Almost a need among some to built “Rube Goldberg machines” for everything. Each time a new issue is raised the solution is to add new functionality or feature to handle it until the system is a complex monstrosity, instead of reevaluating the whole enterprise from first principles in light of new requirements. Our concentration is on design. As I like to say “Code is nice, but design is everything.”, and its corollary “No amount of code ever made up for a poor design.” Our concern was to remain compatible with standards to the extent needed to remain switchable and routable on Ethernet and IP networks, but to reduce the problem of controls messaging to the simplest possible level while retaining a high level of security.

[theamk]

Look, you keep saying "on a suitably reliable network". Where do you get this stuff? TLS replay protection is always present and does not depend on network reliability at all. You might not establish TLS connection if your network is super bad, but it does not mean replay is possible.

Can you PLEASE tell me how unreliable network allows TLS replay (or DTLS replay, or QUIC replay -- they all do key negotiation)