Re: [TLS] Fixing TLS

Hubert Kario <hkario@redhat.com> Wed, 13 January 2016 11:52 UTC

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From: Hubert Kario <hkario@redhat.com>
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Date: Wed, 13 Jan 2016 12:52:27 +0100
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Subject: Re: [TLS] Fixing TLS
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On Tuesday 12 January 2016 17:31:34 Watson Ladd wrote:
> On Tue, Jan 12, 2016 at 5:12 PM, Peter Gutmann
> 
> <pgut001@cs.auckland.ac.nz>; wrote:
> > Yoav Nir <ynir.ietf@gmail.com>; writes:
> > To expand on this, I'll take Ilari Liusvaara's comments:
> >>Bleeding edge ideas? They essentially re-invented SIGMA, which is
> >>over 10 years old. The basic framework for doing 0-RTT is the
> >>obvious one. The only new algorithm prsent since TLS 1.2 is HKDF,
> >>which is just 5 years old.
> >>
> >>So I don't see anything "experimential" ideas, mechanisms or
> >>algorithms in there
> >>
> > When SSLv3 was introduced, it also used ideas that were 10-20 years
> > old (DH, RSA, DES, etc, only SHA-1 was relatively new).  They were
> > mature algorithms, lots of research had been published on them, and
> > yet we're still fixing issues with them 20 years later (DH = 1976,
> > SSLv3 = 1996, Logjam = 2015).
> We all understand that the security of a protocol is not a function
> not of the primitives but of the way the protocol works. The confusion
> between export and nonexport DH shares was noted almost immediately
> in SSLv3. Furthermore, 512 bit DH is weak: I don't know how this is a
> discovery in 2015, given that the reasons for this were all worked
> out in the early 90's. So no, Logjam is not a result of unknown
> issues appearing after 20 years, but ignoring known issues.
> 
> > TLS 2.0-called-1.3 will roll back the 20 years of experience we have
> > with all the things that can go wrong and start again from scratch.
> >  SIGMA, at ten years old, is a relative newcomer to DH's 20 years
> > when it was used in SSLv3, but in either case we didn't discover
> > all the problems with it until after the protocol that used it was
> > rolled out.  We currently have zero implementation and deployment
> > experience with 2.0-called-1.3 [0], which means we're likely to
> > have another 10-20 years of patching holes ahead of us.  This is
> > what I meant by "experimental, bleeding-edge".
> 
> There is an old joke about the resume with one years experience
> repeated 20 times. All of the problems in TLS have been known for
> decades, as I've repeatedly demonstrated on this list. All of them
> were known to cryptographers at the time TLS was being designed and
> deployed. It does not take deployment to trigger analysis.

Exactly this: BEAST and Lucky 13 "possible" problem was described in the 
RFC itself. Same thing for the "new" Bicycle attack - described in the 
RFC for TLS 1.0 and repeated in each version since.

So lets not repeat those mistakes - if there are possible issues, lets 
fix those, now.
-- 
Regards,
Hubert Kario
Senior Quality Engineer, QE BaseOS Security team
Web: www.cz.redhat.com
Red Hat Czech s.r.o., Purky┼łova 99/71, 612 45, Brno, Czech Republic