Re: [TLS] ban more old crap

Viktor Dukhovni <ietf-dane@dukhovni.org> Sat, 25 July 2015 17:18 UTC

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From: Viktor Dukhovni <ietf-dane@dukhovni.org>
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Subject: Re: [TLS] ban more old crap
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On Sat, Jul 25, 2015 at 07:01:42PM +0200, Martin Thomson wrote:

> On 25 July 2015 at 17:48, Salz, Rich <rsalz@akamai.com> wrote:
> > "we" meaning browsers.  "we" not being everyone who will use TLS 1.3
> >
> > Ekr has pointed out a problem; if you connect with a protocol range and proffer RC4, can we do anything about it except point out multiple times that 1.3 servers MUST NOT accept it?
> 
> 
> Agreed.  But I'll point out that other users of TLS will likely not be
> doing fallback either, so they have to deal with offering what they
> support straight up.
> 
> Prohibiting RC4 probably won't do anything more than what our existing
> efforts are doing already.

I would go further, and say that "prohibiting RC4" in any sense
that is more than prohibiting its use as the final outcome of a
handshake would be a rather counter-productive strategy.

Servers and clients are strongly encouraged to not choose it, but
to reject connections from peers that offer it for interoperability
with others would just create a mess that would be operationally
challenging.  RC4 is dying, just let it fade away into insignificance.

-- 
	Viktor.