Re: [TLS] A la carte handshake negotiation

Eric Rescorla <ekr@rtfm.com> Mon, 15 June 2015 13:35 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Mon, 15 Jun 2015 06:34:58 -0700
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To: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
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Subject: Re: [TLS] A la carte handshake negotiation
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On Mon, Jun 15, 2015 at 6:23 AM, Ilari Liusvaara <
ilari.liusvaara@elisanet.fi>; wrote:
>
> Regarding the PSK integration work EKR has been doing in the WIP branch:
>
> 1) Doesn't support identity hints. Now, these might be something nobody
> uses and can be deprecated.
>

My sense was that it was sufficiently rare that we could deprecate it.
It's a bad match for the state machine.



> 2) GDHE_PSK ciphers can't seemingly be safely resumed: Because resumption
> is PSK, it eats the PSK slot, not leaving space for the primary identity.


And your concern here is that you might want to resume GDHE_PSK as ordinary
PSK for performance reasons? If this seems really important, we could
presumably
have multiple PSK slots.

-Ekr