Re: [TLS] A la carte handshake negotiation

Hubert Kario <hkario@redhat.com> Fri, 12 June 2015 14:51 UTC

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From: Hubert Kario <hkario@redhat.com>
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Date: Fri, 12 Jun 2015 16:51:35 +0200
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Subject: Re: [TLS] A la carte handshake negotiation
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On Thursday 11 June 2015 15:58:21 Dave Garrett wrote:
> Here is a branch with a rough draft of an a la carte handshake algorithm
> negotiation scheme for TLS 1.3, based on discussions on this list.
> 
> https://github.com/davegarrett/tls13-spec/compare/updateciphersuites...daveg
> arrett:alacarte
> 
> TL:DR:
> * Deprecate all suites with any of: DH, DHE, ECDH, RSA, DSS
> * Deployments may continue to offer deprecated suites for TLS 1.0-1.2
> negotiation. 
> * TLS 1.3 would only negotiate suites prefixed with
> ECDHE_ECDSA or ECDHE_PSK. 
> * TLS 1.3 implementations negotiate ECDHE/DHE &
> RSA/DSS/ECDSA solely via the "supported_groups" & "signature_algorithms"
> extensions. 
> * No change to bulk cipher negotiation.
> 
> To be clear, this would mean a connection could negotiate usage of a
> ECDHE_ECDSA suite and negotiate ECDHE+RSA. It doesn't say anything about
> DHE+ECDSA yet, but I think that combination is fine if negotiated.

that would require definition of
TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256
TLS_ECDHE_PSK_WITH_256_GCM_SHA384

to keep parity with already existing TLS_DHE_PSK_*

-- 
Regards,
Hubert Kario
Quality Engineer, QE BaseOS Security team
Web: www.cz.redhat.com
Red Hat Czech s.r.o., Purky┼łova 99/71, 612 45, Brno, Czech Republic