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Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1"

Hubert Kario <hkario@redhat.com> Fri, 03 May 2019 15:23 UTC

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From: Hubert Kario <hkario@redhat.com>
To: mrex@sap.com
Cc: tls@ietf.org, Martin Thomson <mt@lowentropy.net>
Date: Fri, 03 May 2019 17:23:28 +0200
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Subject: Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1"
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On Friday, 3 May 2019 16:56:54 CEST Martin Rex wrote:
> Hubert Kario <hkario@redhat.com> wrote:
> > We've been over this Martin, the theoretical research shows that for
> > Merkle- Damgård functions, combining them doesn't increase their security
> > significantly.
> 
> You are completely misunderstanding the results.
> 
> The security is greatly increased!
> 
> Nobody is afraid of the exhaustive search preimage attacks.
> 
> What folks with a little crypto clue are afraid of is
> significantly-faster-than-exhaustive-search real-time preimage attacks.
> And this is where
> 
>   TLSv1.0 + TLSv1.1 (rsa,SHA1+MD5)
> 
> is *significantly* stronger than
> 
>   TLSv1.2 (rsa,MD5) *cough* -- which a depressingly high number of clueless
>           implementers actually implemented, see SLOTH
>   TLSv1.2 (rsa,SHA1)
> 
> 
> That is also trivially formally provable.

I'm eagerly waiting on your published paper on the topic.

-- 
Regards,
Hubert Kario
Senior Quality Engineer, QE BaseOS Security team
Web: www.cz.redhat.com
Red Hat Czech s.r.o., Purkyňova 115, 612 00  Brno, Czech Republic

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