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Re: [TLS] Collisions (Re: Nico's suggestions - Re: Consensus Call: FNV vs SHA1)

Nicolas Williams <Nicolas.Williams@oracle.com> Mon, 10 May 2010 22:35 UTC

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Date: Mon, 10 May 2010 17:34:45 -0500
From: Nicolas Williams <Nicolas.Williams@oracle.com>
To: Stefan Santesson <stefan@aaa-sec.com>
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Cc: Paul Hoffman <paul.hoffman@vpnc.org>, tls@ietf.org
Subject: Re: [TLS] Collisions (Re: Nico's suggestions - Re: Consensus Call: FNV vs SHA1)
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On Tue, May 11, 2010 at 12:29:39AM +0200, Stefan Santesson wrote:
> On 10-05-11 12:15 AM, "Nicolas Williams" <Nicolas.Williams@oracle.com>
> wrote:
> >> Upon a failed cached handshake, the client and server tries a new handshake
> >> without caching, updates it's cache and moves on with life.
> > 
> > Well...  Many applications might not.  Can the handshake be retried
> > transparently to the application?  Or will the application have to
> > close() its socket and re-connect()?
> 
> I agree that the draft may be underspecified here.
> 
> Would it help to say that upon handshake failure using cached information,
> client and servers MUST NOT retry the same handshake using the same cached
> information.

That's part of it, yes.

> I would expect this to be totally transparent to a client application above
> the socket.

Really?  So TLS libraries can do N>=1 failed handshakes without the
application noticing, without re-doing the TCP (or whatever) connection?
What about DTLS?

Nico
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