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Re: [TLS] Analysis of Interop scenarios TLS extension RI w/MCSV

David-Sarah Hopwood <david-sarah@jacaranda.org> Mon, 14 December 2009 03:39 UTC

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Date: Mon, 14 Dec 2009 03:39:14 +0000
From: David-Sarah Hopwood <david-sarah@jacaranda.org>
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Subject: Re: [TLS] Analysis of Interop scenarios TLS extension RI w/MCSV
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Michael Gray wrote:
> I see two use cases here;
> 
> A. Existing implementations that send extensions today and are therefore
> are fine to add this additional extension.  Note: this means they are
> already sending extensions, not just extension capable.  By applying this
> fix nothing changes with the protocol being used.
> 
> B. Existing implementations that do not send any extensions today and as
> such they must not change the protocol due to this fix, which means they
> can only safely use the MCSV as the signaling method.
> 
> It seems to me that we simply need the appropriate wording to allow
> implementers to decide the best strategy that needs to adopted based on
> risk factors to deployed production environments rather than mandate A
> which will break some production environments or mandate B which means that
> extension using systems must use the CipherSuite method.

What is the disadvantage of extension-using systems having to use the
CipherSuite method? I've heard only vague aesthetic objections so far;
nothing concerned with more substantive factors such as code complexity,
security, or interoperability.

> Naturally requiring only one signaling method is simpler and preferable
> from an implementation and testing point of view.

Precisely.

-- 
David-Sarah Hopwood  ⚥  http://davidsarah.livejournal.com

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