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Re: [TLS] RFC 6066 - Max fragment length negotiation

Eric Rescorla <ekr@rtfm.com> Wed, 22 March 2017 02:54 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Tue, 21 Mar 2017 19:53:18 -0700
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To: Martin Thomson <martin.thomson@gmail.com>
Cc: Peter Gutmann <pgut001@cs.auckland.ac.nz>, "tls@ietf.org" <tls@ietf.org>
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Subject: Re: [TLS] RFC 6066 - Max fragment length negotiation
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On Tue, Mar 21, 2017 at 7:03 PM, Martin Thomson <martin.thomson@gmail.com>
wrote:

> On 22 March 2017 at 12:01, Eric Rescorla <ekr@rtfm.com> wrote:
> > The maximum amount of wastage in this case is E_max - E_min where E_min
> is
> > the minimum amount of expansion of any cipher suite they support.
>
> Right, I was concerned about the case where this difference is
> (potentially) large.  That's all.
>
> The main problem I see with a design that shifts complexity to the
> sender is the economic one.  I want to provide as much incentive to
> implement the sender side of this as possible, which means keeping it
> simple.  If the cost of that is a little more complexity on receivers,
> but only when using block ciphers, I think that I can live with that.
> Given that the complexity is likely more in logic than it is code,
> then I'm even more happy with what I've proposed.
>

Sure, I don't think I really care, I just wanted to understand your
reasoning.

-Ekr

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