Re: [TLS] Justification

Michael D'Errico <mike-list@pobox.com> Wed, 12 May 2010 19:27 UTC

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Date: Wed, 12 May 2010 12:15:06 -0700
From: Michael D'Errico <mike-list@pobox.com>
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To: Nicolas Williams <Nicolas.Williams@oracle.com>
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Cc: tls@ietf.org
Subject: Re: [TLS] Justification
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Nicolas Williams wrote:
> 
> Paul Hoffman proposes an extension to add inputs to the Finished message
> computation.  There's no objection yet to Paul's proposal on the grounds
> you state.

Then perhaps it needs to be taken up as a WG item.

> In any case, one of the problems with the caching extension as proposed
> result from not binding the cached objects to the Finished message,
> which at the very least complicates the security analysis of the
> protocol, and possibly compromises it altogether.  We MUST NOT make the
> same mistakes we've made before.

Certainly.  I agree that using the hash value in place of the
actual data could be a huge problem.  Putting the actual data
into the Finished computation probably fixes it.  But the need
to do this takes away all the enthusiasm I originally had for
the cached-info optimization.

Mike