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Re: [TLS] PR for anti-downgrade mechanism

Eric Rescorla <ekr@rtfm.com> Tue, 10 November 2015 00:45 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Mon, 09 Nov 2015 16:44:22 -0800
Message-ID: <CABcZeBMgZdEpH5Y5x676hJpk_nKvxwC3i9BHTYqvLML+8Rhaqw@mail.gmail.com>
To: Christian Huitema <huitema@microsoft.com>
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Subject: Re: [TLS] PR for anti-downgrade mechanism
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On Mon, Nov 9, 2015 at 4:41 PM, Christian Huitema <huitema@microsoft.com>
wrote:

> On Monday, November 9, 2015 4:34 PM, Eric Rescorla wrote:
>
> > On Mon, Nov 9, 2015 at 4:30 PM, Christian Huitema <huitema@microsoft.com>
> wrote:
> >
> >...
> >> Editorial: your proposed text says "...MUST set the first six  bytes of
> its Random value
> >> to the the bytes 44 4F 57 4E 47 52 44 01." I assume you mean the first
> 8 bytes, and that
> >> you do not really want to have "the" twice.
> >
> > Fixed.
>
> Thanks
>
> >> Could you also add a reference to the document that specifies using 44
> 4F  57 4E 47 52
> >> 44 00 by "TLS 1.2 servers which are  negotiating TLS 1.1 or below" ?
> >
> > We don't have one. Wasn't totally sure how to handle that.
>
> I suspected that. Spent sometimes looking for text in published RFC, could
> not find it. I suspect that many readers will fall in the same trap and
> lose some time. Could you add text explaining that this is an undocumented
> feature of some implementations, and that we are recommending its use? Or
> something to that effect...
>

Worse, we just invented it. What about if I say "TLS 1.2 servers SHOULD..."

-Ekr


>
> -- Christian Huitema
>
>
>
>

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