Re: [TLS] CCS and key reset and renegotiation

Viktor Dukhovni <viktor1dane@dukhovni.org> Thu, 05 June 2014 16:42 UTC

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Date: Thu, 5 Jun 2014 16:42:42 +0000
From: Viktor Dukhovni <viktor1dane@dukhovni.org>
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Subject: Re: [TLS] CCS and key reset and renegotiation
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On Thu, Jun 05, 2014 at 08:25:26AM -0700, Watson Ladd wrote:

> > I think it adds weight to my concern about using ChangeCipherSpec to do
> > key reset.  I still prefer the trade-offs of having a ?slow the TLS but
> > keep the TCP layer open? and starting over.  Much simpler to prove it?s
> > correct.
> 
> What can change when that happens? Furthermore, rekeying is a matter of
> getting more PRF output: how does that introduce security concerns.

Whether or not rekeying is easier to implement with a STOPTLS, or
by switching directly from one keyset to another, without an
intermediate transition to cleartext, a STOPTLS feature has additional
upside.  I don't recall whether this idea got dropped, or whether
STOPTLS might yet happen in TLS 1.3.  Anyone care to bring me up
to speed?

-- 
	Viktor.