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Re: DH Group Exchange in SSH (RFC 4419) - Avoiding Backsdoors

Damien Miller <djm@mindrot.org> Thu, 29 September 2016 17:29 UTC

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Date: Fri, 30 Sep 2016 03:28:54 +1000
From: Damien Miller <djm@mindrot.org>
To: "Mark D. Baushke" <mdb@juniper.net>
cc: ietf-ssh@NetBSD.org, curdle@ietf.org, frg@irtf.org
Subject: Re: DH Group Exchange in SSH (RFC 4419) - Avoiding Backsdoors
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On Thu, 29 Sep 2016, Mark D. Baushke wrote:

> Hi,
> 
> Question:
> 
> Should RFC 4419 - "Diffie-Hellman Group Exchange for the Secure Shell
> (SSH) Transport Layer Protocol" be deprecated?
> 
> Background:
> 
> The paper "How to Backdoor Diffie-Hellman" by David Wong
> https://eprint.iacr.org/2016/644.pdf describes two ways
> of creating a Nobody-But-Us (NOBUS) Diffie-Hellman backdoor:

NOBUS backdoors aren't the only concern; another motivation was
logjam-style precomputation attacks.

-d

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