Re: [TLS] Wrapping up cached info

Nicolas Williams <Nicolas.Williams@oracle.com> Thu, 27 May 2010 15:48 UTC

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Date: Thu, 27 May 2010 10:47:17 -0500
From: Nicolas Williams <Nicolas.Williams@oracle.com>
To: Brian Smith <brian@briansmith.org>
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Subject: Re: [TLS] Wrapping up cached info
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On Thu, May 27, 2010 at 10:38:09AM -0500, Brian Smith wrote:
> Martin Rex wrote:
> > I think that should be described in the Security Considerations that
> > a client or client&server that perform renegotiation for the purpose
> > of client identity protection may want to tag their cached values
> > so that when that value was established on an encrypted handshake,
> > it is not going to be proposed by the client on a successor
> > plaintext handshake.

Yes.

> How would the server indicate this to the client?

There's no need for the server to indicate anything to the client here.

If a client wouldn't attempt user authentication w/o re-negotiation then
it shouldn't send a hash of its user cert / cert chain in the initial
handshake.  If a server considers user cert TAs to be confidential
(highly unlikely, but let's suppose) then the server shouldn't list
their hashes in initial handshakes.  It's that simple.

Nico
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