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Re: [TLS] PR for anti-downgrade mechanism

Dave Garrett <davemgarrett@gmail.com> Fri, 09 October 2015 20:14 UTC

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From: Dave Garrett <davemgarrett@gmail.com>
To: tls@ietf.org, Viktor Dukhovni <ietf-dane@dukhovni.org>
Date: Fri, 09 Oct 2015 16:14:05 -0400
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Subject: Re: [TLS] PR for anti-downgrade mechanism
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On Friday, October 09, 2015 12:49:02 pm Viktor Dukhovni wrote:
> I think this is "too clever" (a "hack" not a design) and offers

Every fix to an issue in this 20 year old protocol will be a hack.

> incomplete protection (does nothing to protect RSA key transport).

Better than none, for a very low cost.

> So I do not support adoption of this proposal.
> 
> If new attacks against TLS 1.0--1.2 emerge that enable MITM via
> version downgrade combined with use of weaker algorithms, then
> we'll just have to prohibit those weaker algorithms in TLS 1.3
> servers (and possibly also clients).

Those changes are harder to make than they should be, unless we want to do that now.


Dave

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