Re: [TLS] Adoption call for Deprecating Obsolete Key Exchange Methods in TLS

Peter Gutmann <pgut001@cs.auckland.ac.nz> Sun, 01 August 2021 11:42 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: "tls@ietf.org" <tls@ietf.org>
Thread-Topic: [TLS] Adoption call for Deprecating Obsolete Key Exchange Methods in TLS
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Archived-At: <https://mailarchive.ietf.org/arch/msg/tls/MElP024DoIJZHucSKtEEZiQN1Pk>
Subject: Re: [TLS] Adoption call for Deprecating Obsolete Key Exchange Methods in TLS
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Viktor Dukhovni <ietf-dane@dukhovni.org> writes:

>OK, who goes around bothering to actually generate custom DH parameters, and
>with what tools, but then does not use a "strong" (Sophie Germain) prime?

That's better :-).  That was my thought too, every DH/DLP keygen I've seen
generates either Sophie Germain or FIPS 186 primes/parameters, so on the off
chance that your server feels like generating custom primes you'd need to go
out of your way to generate unsuitable ones, i.e. you'd probably need to write
custom code specifically for bad prime generation, and if you're going to do
that then all bets are off anyway.

Peter.