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Re: [TLS] "Encrypted" SNI

Hubert Kario <hkario@redhat.com> Thu, 11 May 2017 11:01 UTC

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From: Hubert Kario <hkario@redhat.com>
To: Ilari Liusvaara <ilariliusvaara@welho.com>
Cc: "tls@ietf.org" <tls@ietf.org>
Date: Thu, 11 May 2017 12:59:40 +0200
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Subject: Re: [TLS] "Encrypted" SNI
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On Wednesday, 10 May 2017 21:28:48 CEST Ilari Liusvaara wrote:
> On Wed, May 10, 2017 at 07:28:51PM +0200, Hubert Kario wrote:
> > Yes, encrypted SNI was discussed and ultimately rejected.
> > 
> > But do we really have to send the literal value? Don't we need to just
> > make
> > sure that the client and server agree on the host that the client wants to
> > connect?
> > 
> > Couldn't we "encrypt" the SNI by hashing the host name with a salt,
> > sending
> > the salt and the resulting hash, making the server calculate the same hash
> > with each of the virtual host names it supports and comparing with the
> > client provided value?
> 
> What makes encrypting SNI nasty is replay attacks.

What if we specify that the salt is the client key share?


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

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