Hi Éric, Trimming heavily, as several other responses have landed already...
On Mon, Apr 19, 2021 at 12:47:51AM -0700, Éric Vyncke via Datatracker wrote: > > > ---------------------------------------------------------------------- > COMMENT: > ---------------------------------------------------------------------- > > -- Section 3 -- > While I am not a DTLS expert, I find this section quite difficult to > understand > the reasoning behind the specification as little explanations are given about, > e.g, what is the motivation of "A zero-length value indicates that the server > will send with the client's CID but does not wish the client to include a > CID." We had a lot of discussion in the WG about zero-length CIDs and the various edge cases that can arise. (You might imagine, for example, wanting to use the new record format and get content-type confidentiality even when a CID is not needed for routing messages.) We ended up concluding that it's simpler and safer to do what's described now -- no CID means the RFC 6347 record format. But the discussion in the document may not have captured the full extent of the WG discussion, so we can take a look at whether there is more to be said. The short answer is that this is a typical mechanism where each part tells the other how to contact them, but in order to confirm the negotiation to use the feature, we need a signal for "I don't need a CID but I support CIDs", and the zero-length field in the handshake packets plays that role quite naturally. -Ben _______________________________________________ TLS mailing list [email protected] https://www.ietf.org/mailman/listinfo/tls
