SPECTRA — Kernel Exchange needs clarifications

Review 16-05-2025

Exchange –
o Definition: it is common in some networks, especially of the hub architecture, to have a single producer create a data element that multiple consumers consume. Or to have multiple producers create a data item that a single consumer consumes. The definition (and model) of Exchange says it’s a single producer to single consumer. I believe this will limit its usability in many systems.
o Semantics: I do not believe this semantically assertion made here is true. There are sometimes where the message is encrypted along the channel path without knowledge or involvement of the direct producer or consumer. There are intermediate “nodes” between a producer and consumer that are often transparent to the message sender or recipient.

NM: With regards to the definition, this must be aligned with SysML and AAR. The current practice (AAR/CSV and SysML) for the situation of multiple consumers is to duplicate exchanges. Depending on the kind of attack, usually only a specific exchange is impacted. Regarding encryption: in a thread/dataflow that traverses multiple channel segments, there are multiple exchanges involved. If encryption is transparent to the end nodes, then the initial and final exchanges are not encrypted, but at least one exchange involved in the thread is. Exchange is supported by some capability of both the sender and the receiver, e.g. protocol support. In case of encryption, there is key management and exchange. Understanding exactly which exchanges are encrypted and which are not is important to understand bypass, and data leaks.