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Date: Tue, 04 Nov 2025 18:38:23 +0100
From: "Filippo Valsorda" <filippo@ml.filippo.io>
To: "Nick Sullivan" <nicholas.sullivan@gmail.com>,
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2025-11-04 18:17 GMT+01:00 Nick Sullivan <nicholas.sullivan@gmail.com>:
> The stakeholders with the strongest preference for maintaining
> compatibility appear to be library implementers, who would likely need
> to add a new codepoint to their libraries to support existing non-IETF
> use cases and any RFC that relies on concrete hybrids as normative.
> Which is less than ideal, but maybe not catastrophic. The good news is
> that almost all existing implementations use the term X-Wing, X-Wing
> and X25519-MLKEM512 are very different names, so confusion may be
> minimal among users.

To be clear, and to echo David Benjamin, I am not saying that adding a codepoint for the incompatible CFRG variant would be confusing, I am saying I am not interested in shipping a needlessly incompatible variant of an already deployed construction at all.

Anyway, aside from whatever CFRG consensus is reached, I believe we do indeed need to have an IETF conversation around relying on CFRG documents as normative references, and around moving WG work at RG speeds.
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<!DOCTYPE html><html><head><title></title></head><body><div>2025-11-04 1=
8:17 GMT+01:00 Nick Sullivan &lt;<a href=3D"http://nicholas.sulliva">nic=
holas.sulliva</a>n@<a href=3D"http://gmail.com">gmail.com</a>&gt;:<br></=
div><blockquote type=3D"cite" id=3D"qt" style=3D""><div>The stakeholders=
 with the strongest preference for maintaining</div><div>compatibility a=
ppear to be library implementers, who would likely need</div><div>to add=
 a new codepoint to their libraries to support existing non-IETF</div><d=
iv>use cases and any RFC that relies on concrete hybrids as normative.</=
div><div>Which is less than ideal, but maybe not catastrophic. The good =
news is</div><div>that almost all existing implementations use the term =
X-Wing, X-Wing</div><div>and X25519-MLKEM512 are very different names, s=
o confusion may be</div><div>minimal among users.<br></div></blockquote>=
<div><br></div><div>To be clear, and to echo David Benjamin, I am not sa=
ying that adding a codepoint for the incompatible CFRG variant would be =
confusing, I am saying I am not interested in shipping a needlessly inco=
mpatible variant of an already deployed construction at all.</div><div><=
br></div><div>Anyway, aside from whatever CFRG consensus is reached, I b=
elieve we do indeed need to have an IETF conversation around relying on =
CFRG documents as normative references, and around moving WG work at RG =
speeds.</div></body></html>
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