Re: [TLS] analysis of wider impact of TLS1.3 replayabe data

Viktor Dukhovni <ietf-dane@dukhovni.org> Mon, 14 March 2016 17:36 UTC

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From: Viktor Dukhovni <ietf-dane@dukhovni.org>
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Date: Mon, 14 Mar 2016 13:36:27 -0400
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Subject: Re: [TLS] analysis of wider impact of TLS1.3 replayabe data
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> On Mar 13, 2016, at 7:14 AM, Stephen Farrell <stephen.farrell@cs.tcd.ie>; wrote:
> 
> So, can people suggest ways in which we can figure out the impact
> of replayable data across all the many uses of TLS?

For idempotent (more strongly side-effect free) lookup protocols, 0-RTT makes
good sense.  There is no need for replay protection in the absence of
side-effects.  Web browsers are not the only use-case for TLS.

Similarly, in SMTP with STARTTLS the client's first data payload is a repeat
of an EHLO command that was already sent in the clear!  So one might for example
send the client's EHLO as 0-RTT replayable data.  Of course SMTP servers that
support 0-RTT data don't exist yet, but they may once 0-RTT becomes widely
available in SSL/TLS toolkits.

-- 
	Viktor.