Re: [TLS] Re: Russ Housley: Fwd: problems with

Martin Rex <martin.rex@sap.com> Mon, 03 July 2006 14:20 UTC

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From: Martin Rex <martin.rex@sap.com>
Message-Id: <200607031420.QAA06616@uw1048.wdf.sap.corp>
Subject: Re: [TLS] Re: Russ Housley: Fwd: problems with
To: ekr@networkresonance.com
Date: Mon, 3 Jul 2006 16:20:21 +0200 (MET DST)
In-Reply-To: <86psgoj0e2.fsf@raman.networkresonance.com> from "Eric Rescorla" at Jul 1, 6 05:50:13 pm
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Eric Rescorla wrote:
> 
> >> In particular, this advice does not match with current TLS practice,
> >> which is NOT to check for weak keys.
> >
> > It is a security consideration, and I present it for consideration as
> > such.  Let's consider the (admittedly unlikely, but also admittedly
> > possible) case of DES with an all-zero key, or 3DES with an all-zero
> > key.  Surprise!  Identity operation!  Would you want /your/ medical or
> > financial data protected over a network that had implementations that
> > could possibly not encrypt it at all?
> 
> Yes, I'm quite familiar with the issue. And yes, I'm quite comfortable
> with the current situation.

Although the existing SSL/TLS specs do not define how to synchronously
skip/drop weak keys during key generation upfront and synchronously,
wouldn't it be possible for either side (when the particular implementations
feels such a need) to detect a weak key and force the peer directly
through a renegotiate -- even old peers?

-Martin

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