Re: [TLS] Ala Carte Cipher suites - was: DSA should die

Geoffrey Keating <geoffk@geoffk.org> Mon, 13 April 2015 23:15 UTC

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To: Yoav Nir <ynir.ietf@gmail.com>
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From: Geoffrey Keating <geoffk@geoffk.org>
Date: 13 Apr 2015 16:15:39 -0700
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Subject: Re: [TLS] Ala Carte Cipher suites - was: DSA should die
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Yoav Nir <ynir.ietf@gmail.com> writes:

> > On Apr 14, 2015, at 12:09 AM, Geoffrey Keating <geoffk@geoffk.org> wrote:

> > In particular I don't think we've simplified anything if
> > implementations have to have a list of invalid combinations, or have
> > to know that certain ciphers are to be used only with matching key
> > exchange algorithms (for example, use the GOST key exchange with the
> > GOST symmetric cipher).
> 
> Why?  There’s nothing invalid about using Curve25519 key exchange
> with an RSA certificate and GOST symmetric ciphers, so TLS should
> not provide this. Requiring all three things to be GOST is a policy
> decision that can and should be part of server (and perhaps client)
> configuration.

It seems like that would be an interoperability issue if the server
and client disagree on the policy to apply.