Re: [TLS] Computation of static secret in anonymous DH
Ilari Liusvaara <ilari.liusvaara@elisanet.fi> Fri, 31 July 2015 16:42 UTC
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Date: Fri, 31 Jul 2015 19:42:12 +0300
From: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
To: Nico Williams <nico@cryptonector.com>
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Subject: Re: [TLS] Computation of static secret in anonymous DH
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On Fri, Jun 26, 2015 at 01:41:29PM -0500, Nico Williams wrote: > > tls-unique depends on the Finished message strongly binding the entire > transcript up to that point. I find this elegant (despite the > resumption problem, which anyways, should be fixed by the session hash) > and easy to understand and analyze. > > If the Finished message no longer has this property in 1.3 then that's a > problem for tls-unique, and we'd have to fix one or the other. Surely > 1.3 will have some handshake message that binds the transcript, and why > that wouldn't be the Finished message is beyond me (but I am missing a > lot of the 1.3 context, so please forgive and inform me). Also, it turns out some are assuming tls-unique is both connection nonce and secret value. :-/ I don't think the present construct for Finished values is appropriate for such values, which means one would have to redefine tls-unique so it meets the need. (TLS-Exporter values already look to be secret and connection nonces, and I have already seen stuff relying on both properties). Basically, the value needs to derive from both "master secret" (to make it secret) and session hash /w configs (to make it connection nonce). -Ilari
- [TLS] Computation of static secret in anonymous DH Douglas Stebila
- Re: [TLS] Computation of static secret in anonymo… Ilari Liusvaara
- Re: [TLS] Computation of static secret in anonymo… Eric Rescorla
- Re: [TLS] Computation of static secret in anonymo… Ilari Liusvaara
- Re: [TLS] Computation of static secret in anonymo… Eric Rescorla
- Re: [TLS] Computation of static secret in anonymo… Ilari Liusvaara
- Re: [TLS] Computation of static secret in anonymo… Eric Rescorla
- Re: [TLS] Computation of static secret in anonymo… Ilari Liusvaara
- Re: [TLS] Computation of static secret in anonymo… Eric Rescorla
- Re: [TLS] Computation of static secret in anonymo… Nico Williams
- Re: [TLS] Computation of static secret in anonymo… Eric Rescorla
- Re: [TLS] Computation of static secret in anonymo… Hugo Krawczyk
- Re: [TLS] Computation of static secret in anonymo… Eric Rescorla
- Re: [TLS] Computation of static secret in anonymo… Ilari Liusvaara
- Re: [TLS] Computation of static secret in anonymo… Eric Rescorla
- Re: [TLS] Computation of static secret in anonymo… Hubert Kario
- Re: [TLS] Computation of static secret in anonymo… Ilari Liusvaara
- Re: [TLS] Computation of static secret in anonymo… Nico Williams