We spent a fair bit of time working to shrink the DTLS 1.3 record layer, so I'm not sure how much room there is for optimization. See: https://www.rfc-editor.org/rfc/rfc9147.html#name-the-dtls-record-layer
Specifically, the longest header (w/o CID) is 5 octets and the shortest is 2 octets. The sequence number is used for the IV, so there's no extra there. -Ekr On Mon, May 30, 2022 at 6:28 AM Robert Moskowitz <[email protected]> wrote: > Greetings Hannes, > > This is for the record layer. And I really don't know how much would be > gained. > > But as I would see it, this use of SCHC would be for UDP/DTLS/cipher. > Since it is starting with UDP, SCHC would have to be an IP Protocol (not > currently defined as such). So you loose 1 byte for the SCHC rule, against > the 8 probably saved in compressing UDP to 0 bytes. Then there is the > cipher. Try AES-GCM-12; what is currently used for the IV? Can something > like rfc8750 be added to use the seq # in the DTLS header and gain maybe 16 > bytes? I really don't know the DTLS header at all. I have tried to find > some decent layout as I am use to for ESP in 4303 (Fig 1) for side-by-side > comparison. > > But if it means being able to fit over some UHF carrier for unmanned > aircraft (UA) Network Remote ID (Net-RID) and Command and Control (C2)? > Worth the effort. > > So this is not something I could do myself, but something that I see using > and thus pitching in on doing it. > > On 5/30/22 05:33, Hannes Tschofenig wrote: > > Bob, is this about compressing the DTLS record layer or the DTLS handshake > protocol? > > For the former, I wonder how much is there actually to compress (when > using DTLS 1.3)? > > > > *From:* TLS <[email protected]> <[email protected]> *On Behalf Of * > Eric Rescorla > *Sent:* Friday, May 27, 2022 5:30 PM > *To:* Robert Moskowitz <[email protected]> <[email protected]> > *Cc:* <[email protected]> <[email protected]> <[email protected]> <[email protected]> > *Subject:* Re: [TLS] SCHC for DTLS > > > > > > > > On Fri, May 27, 2022 at 6:27 AM Robert Moskowitz <[email protected]> > wrote: > > Is there any activity to define SCHC rules for DTLS? > > > > Not to my knowledge. > > > > -Ekr > > > > > I want this for Unmanned Aircraft (UA) Network Remote ID (Net-RID) > communications from the UA to the Net-RID Service Provider (SP). > > See > > https://datatracker.ietf.org/doc/draft-moskowitz-drip-secure-nrid-c2/ > > I am compressing ESP traffic using rfc 8750 and: > > https://datatracker.ietf.org/doc/draft-mglt-ipsecme-diet-esp/ > > SCHC is negotiated in IKE (and will be in HIP) and SA tables allow the > ESP receiver to recognize a SCHC compressed ESP Header and act properly. > > It is not so simple with DTLS. First UDP is below DTLS, so how do you > compress it? The way I see it, SCHC would need to be assigned an IP > Protocol type so that the transport processing can start right up with > the SCHC rule for UDP and then on to DTLS and then the cipher. > > Or at least how I see the challenge. > > So I am looking for any extant work on SCHC for DTLS and/or interest in > this activity. > > The CoAP SCHC work, rfc 8824, dodge DTLS compression. Or that is how I > read it. > > Thanks > > Bob > > _______________________________________________ > TLS mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/tls > > IMPORTANT NOTICE: The contents of this email and any attachments are > confidential and may also be privileged. If you are not the intended > recipient, please notify the sender immediately and do not disclose the > contents to any other person, use it for any purpose, or store or copy the > information in any medium. Thank you. > > >
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