>X25519MLKEM768 should be ranked higher than X. What is X?

Agree that this does not make sense. I think the reasonable thing with 
X25519MLKEM768 it to make it MTI. That makes sense given that Cloudflare report 
70% use in CHs.

>client should rank PQ keyshares higher than non-PQ shares.

Yes please.

>But that would mean ranking some recommended=N keyshares higher than 
>recommended=Y shares.

I think that just illustrates how broken the RECOMMENDED mechanism is.

> Do we need to say anything about HRR? Should a server HRR when the client 
> sends a non-PQ share, but it and the server do support a PQ share?

Yes, I think  the server should try to get a PQ shares.

(Should be “when the client does not send a PQ share", as the client might not 
send a share in CH)

Cheers,
John Preuß Mattsson

From: Bas Westerbaan <[email protected]>
Date: Thursday, 30 April 2026 at 11:11
To: Bellebaum, Thomas <[email protected]>
Cc: [email protected] <[email protected]>
Subject: [TLS] Re: Working group adoption call for 
draft-westerbaan-tls-keyshare-recommendations-02


I would be happy about a recommendation of hybrids over these curves in text 
form (e.g. "Clients and servers SHOULD rank X25519MLKEM768 higher"), if this is 
easy to embed in the process chosen to adopt this document's change.

I like the idea and started to draft a PR, but figuring out the actual wording 
is not that straightforward.

1. X25519MLKEM768 should be ranked higher than X. What is X? All other (future) 
keyshares? Listing the non-PQ recommended=Y keyshares explicitly? The most 
direct advise would be that client should rank PQ keyshares higher than non-PQ 
shares. But that would mean ranking some recommended=N keyshares higher than 
recommended=Y shares.

2. Do we need to say anything about HRR? Should a server HRR when the client 
sends a non-PQ share, but it and the server do support a PQ share?

Best,

 Bas
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