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Re: [TLS] Remove DH-based 0-RTT

Bill Cox <waywardgeek@google.com> Wed, 24 February 2016 02:38 UTC

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Date: Tue, 23 Feb 2016 18:38:31 -0800
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From: Bill Cox <waywardgeek@google.com>
To: Andrei Popov <Andrei.Popov@microsoft.com>
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Subject: Re: [TLS] Remove DH-based 0-RTT
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+1

On Tue, Feb 23, 2016 at 12:02 PM, Andrei Popov <Andrei.Popov@microsoft.com>
wrote:

> For general-purpose TLS stacks that have to support PSK anyway (and
> therefore already deal with PSK persistence issues), removing DH-based
> 0-RTT is a significant simplification.
>
> Cheers,
>
> Andrei
>
> -----Original Message-----
> From: TLS [mailto:tls-bounces@ietf.org] On Behalf Of Martin Thomson
> Sent: Tuesday, February 23, 2016 11:39 AM
> To: Wan-Teh Chang <wtc@google.com>
> Cc: tls@ietf.org
> Subject: Re: [TLS] Remove DH-based 0-RTT
>
> On 23 February 2016 at 11:24, Wan-Teh Chang <wtc@google.com> wrote:
> > It seems sufficient to just ban client authentication in replayable
> > DH-based 0-RTT. Why remove DH-based 0-RTT altogether?
>
> On the grounds that it is more complex to analyze, build, and test.
> And given that deferring the feature does no significant harm to those who
> want it.
>
> I acknowledge that persistence of secrets on clients is a material
> difference between that an PSK-based 0-RTT.  I just don't think that it's a
> good enough reason to pay for what is a relatively expensive feature.
>
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