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Re: [TLS] Working Group Last Call for draft-ietf-tls-downgrade-scsv-00

Martin Thomson <martin.thomson@gmail.com> Fri, 26 September 2014 07:02 UTC

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Date: Fri, 26 Sep 2014 08:01:55 +0100
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From: Martin Thomson <martin.thomson@gmail.com>
To: Bodo Moeller <bmoeller@acm.org>
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Subject: Re: [TLS] Working Group Last Call for draft-ietf-tls-downgrade-scsv-00
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On 26 September 2014 07:54, Bodo Moeller <bmoeller@acm.org> wrote:
> What specifically do you consider wasteful?

16 bits, that's all.  Not a big deal (unless you are close to having to pad...)

> Note that ignoring the SCSV *on resumption* wouldn't quite work. The server
> would need to ignore the SCSV on resumption *attempts*, successful or not; I
> don't think I'd like that.

The draft requires that downgrade on resumption attempts (yes, you are
completely correct) is not guarded.  Whether that's a requirement on
the server or client doesn't seem like a big deal to me.

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