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Re: [TLS] PR for anti-downgrade mechanism

Brian Smith <brian@briansmith.org> Fri, 16 October 2015 20:39 UTC

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Date: Fri, 16 Oct 2015 10:39:24 -1000
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From: Brian Smith <brian@briansmith.org>
To: Martin Thomson <martin.thomson@gmail.com>
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Cc: Karthikeyan Bhargavan <karthik.bhargavan@gmail.com>, "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] PR for anti-downgrade mechanism
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On Fri, Oct 16, 2015 at 10:04 AM, Martin Thomson <martin.thomson@gmail.com>
wrote:

> On 16 October 2015 at 12:22, Brian Smith <brian@briansmith.org> wrote:
> > Why only protect TLS 1.3 from such a downgrade? I think it is worthwhile
> to
> > protect TLS 1.2 from the downgrade too, in a similar way. Or, is there
> > something specific about TLS 1.3 that makes the downgrade worse?
>
> Given that we can't expect TLS 1.2 servers to implement the hack, I'm
> not sure that this is of great utility, but if we can bake a version
> number in there, I'm not opposed to the notion.
>

I think TLS 1.2 servers would implement the mechanism, if it were
documented in an update to the downgrade-scsv document. I mean, this
mechanism is basically a replacement for the downgrade-scsv mechanism,
because the downgrade-scsv mechanism doesn't (at least, can't be proven) to
work, right? That would be especially true for an implementation that does
False Start for TLS 1.2.

Cheers,
Brian
-- 
https://briansmith.org/

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