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

mrex@sap.com (Martin Rex) Mon, 06 May 2019 23:57 UTC

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To: Hubert Kario <hkario@redhat.com>
Date: Tue, 7 May 2019 01:57:30 +0200 (CEST)
CC: mrex@sap.com, tls@ietf.org, Martin Thomson <mt@lowentropy.net>
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From: mrex@sap.com (Martin Rex)
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Subject: Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1"
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Hubert Kario <hkario@redhat.com> wrote:
> 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!
> 
> like I said, that were the follow up papers
> 
> the original is still Joux:
> https://www.iacr.org/archive/crypto2004/31520306/multicollisions.pdf

Thanks to Peter Gutmann for the summary:

    https://mailarchive.ietf.org/arch/msg/tls/g0MDCdZcHsvZefv4V8fssXMeEHs

which you may have missed.

> 
>>   TLSv1.2 (rsa,MD5) *cough* -- which a depressingly high number of clueless
>>           implementers actually implemented, see SLOTH
> 
> SLOTH?

SLOTH is a brainfart in the TLSv1.2 spec which is blatently obvious.

If (md5,rsa) was actually shipped in a TLSv1.2 implementation, it indicates
a dysfunctional (or crypto-clueless) QA for the project.


The erroneous implementation of (md5,rsa) was silently removed from openssl
*without* CVE, after I privately complained about this brainfart having
been added to openssl.


I ranted about the TLSv1.2 digitally_signed brainfart in rfc5246 on
the IETF TLS WG mailing list here (01-Oct-2013):

    https://mailarchive.ietf.org/arch/msg/tls/l_R94xX7myvL9x8I_7L7NiDjV9w

assuming that crypto clue and common sense should work.

Looking at what was still affected by the problem end of 2014,
it seems that you *MUST* hit TLS implementors with a CVE

    https://www.mitls.org/pages/attacks/SLOTH#disclosure

and can not rely on crypto-clue and common sense.


-Martin