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Re: [TLS] A suggestion for handling large key shares

Rob Sayre <sayrer@gmail.com> Tue, 19 March 2024 20:36 UTC

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From: Rob Sayre <sayrer@gmail.com>
Date: Tue, 19 Mar 2024 13:36:02 -0700
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To: Bas Westerbaan <bas=40cloudflare.com@dmarc.ietf.org>
Cc: "Scott Fluhrer (sfluhrer)" <sfluhrer=40cisco.com@dmarc.ietf.org>, "TLS@ietf.org" <tls@ietf.org>
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Subject: Re: [TLS] A suggestion for handling large key shares
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On Tue, Mar 19, 2024 at 12:41 AM Bas Westerbaan <bas=
40cloudflare.com@dmarc.ietf.org> wrote:

> Hi Scott,
>
> I generally agree with David, in particular that the keyshare prediction
> draft is the way forward.
>

Hi,

David did not like this idea, but it's also possible to bake this
preference into ECH. If your ECHConfig requires a certain keyshare,
say X25519+Kyber, then you can enforce this choice.* This way is more
brittle for sure, but you can enforce the requirement.

thanks,
Rob

*
https://datatracker.ietf.org/doc/html/draft-ietf-tls-esni#config-extensions-guidance

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