Re: [TLS] WGLC: draft-ietf-tls-prohibiting-rc4-00

mrex@sap.com (Martin Rex) Fri, 08 August 2014 14:57 UTC

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To: Hubert Kario <hkario@redhat.com>
Date: Fri, 8 Aug 2014 16:56:58 +0200 (CEST)
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From: mrex@sap.com (Martin Rex)
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Subject: Re: [TLS] WGLC: draft-ietf-tls-prohibiting-rc4-00
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Hubert Kario wrote:
> 
>> There currently exists *no* known attack against the integrity
>> protection of the TLS handshake, so this looks primarily like an
>> attempt to promote "planned obsolesence", and a poor excuse for
>> Microsoft to actively break interop with Windows XP (and potentially
>> other installed base).
> 
> 3DES remains an option if you need to interoperate with very old
> systems. It doesn't break interoperability with Windows XP.
> 
>  0 - http://blog.cloudflare.com/killing-rc4-the-long-goodbye


This is the theory.
In theory, theory an practice are the same, in practice they differ.

There seems to be stuff that breaks with TLS cipher suites that
use padding.  This is just Windows stuff, I've also seen such
interop problems with Java (J2SE) client (using nio it seems),
that will simply not interop with 3DES-EDE (nor AES128-SHA),
and RC4 is the only alternative that works.

-Martin