Re: [TLS] A la carte handshake negotiation

Peter Gutmann <pgut001@cs.auckland.ac.nz> Mon, 29 June 2015 08:58 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Nico Williams <nico@cryptonector.com>, Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
Date: Mon, 29 Jun 2015 08:58:11 +0000
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Subject: Re: [TLS] A la carte handshake negotiation
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 Nico Williams <nico@cryptonector.com>; writes:
>On Sun, Jun 28, 2015 at 10:44:03AM +0300, Ilari Liusvaara wrote:
>
>>"Chinese menus" with coupled choices are classical source of interop
>>problems.
>
>It's worked for SSHv2.

It worked for SSH because implementations use algorithm groups in highly 
stereotyped ways, so you have a de facto interop profile. Try negotiating 
e.g. RC4+SHA in one direction and AES+SHA2 in the other and see how quickly 
the wheels fall off.

Peter.