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Re: [TLS] 0RTT and HelloRetryRequest (Re: Narrowing the replay window)

Martin Thomson <martin.thomson@gmail.com> Thu, 31 March 2016 01:18 UTC

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Date: Thu, 31 Mar 2016 12:18:45 +1100
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From: Martin Thomson <martin.thomson@gmail.com>
To: Eric Rescorla <ekr@rtfm.com>
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Subject: Re: [TLS] 0RTT and HelloRetryRequest (Re: Narrowing the replay window)
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On 31 March 2016 at 09:59, Eric Rescorla <ekr@rtfm.com> wrote:
>> Option 2 suits best if we consider HelloRetryRequest to be a DoS feature
>> exclusively or at least primarily. But we have other reasons for it and I
>> don't think that DoS mitigation is a big factor for TCP.
>
>
> I believe Option #2 is simplest.

I didn't mention this because I was composing on a phone at the time,
but we have to decide whether to allow a second attempt at 0-RTT.  If
we do, then the effect is a two round trip setback.  I think that the
odds of this happening are small, so I'm OK with it, but I wanted to
highlight that.

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