Re: [TLS] Resumption ticket/PSK

[Viktor Dukhovni <[e-mail]>]

On Thu, May 19, 2016 at 04:37:30PM -0400, Martin Thomson wrote:

> On 19 May 2016 at 16:01, Viktor Dukhovni <[e-mail]> wrote:
> > Nevertheless, some clients may want to attempt to gain fine-grained
> > protection against correlating back to back or parallel resumption
> > requests.  For this they'd have to ensure that all session tickets
> > are single use, and either perform new handshakes when increasing
> > the number of parallel connections to the server, or somehow obtain
> > more than one ticket within a single session.
> 
> I believe that this is the intent of the PR.  I've suggested an
> alternative wording that cleaves closer to your text above.

I'm suggesting that instead of servers guessing that clients want
this, it might make more sense to employ an extension to request
single-use tickets.  Session tickets will often encapsulate the
client certificate, and issuing them on every resumption can
considerably increase the size of the server response.  Many clients
will not benefit, so I'm suggesting that this should be optional.

I've not heard many others chime-in yet, so it is not yet clear
where WG consensus may lie on this question.

-- 
	Viktor.