Re: [TLS] WGLC for draft-ietf-tls-tls13-cert-with-extern-psk

"Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu> Fri, 31 May 2019 21:59 UTC

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From: "Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu>
To: Geoff Keating <geoffk@geoffk.org>, IETF TLS <tls@ietf.org>
Thread-Topic: [TLS] WGLC for draft-ietf-tls-tls13-cert-with-extern-psk
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Date: Fri, 31 May 2019 21:59:00 +0000
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Subject: Re: [TLS] WGLC for draft-ietf-tls-tls13-cert-with-extern-psk
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On 5/31/2019, 17:34, "TLS on behalf of Geoff Keating" <tls-bounces@ietf.org on behalf of geoffk@geoffk.org>; wrote:
    >> On 21 May 2019, at 2:08 pm, Hugo Krawczyk <hugo@ee.technion.ac.il>; wrote:
    >> 
    >> A clarification on the text suggest below by Russ.
    >> 
    >> The way I see it, the external PSK as used in draft-ietf-tls-tls13-cert-with-extern-psk is not intended as
    >> a means of authentication but as a way of regaining forward secrecy in case the (EC)DHE mechanism
    >>  is ever broken (e.g., by cryptanalysis or by a quantum computer).
    >
    >  It’s a bit problematic if the expected use of the draft is with quantum-resistant
    >  certificates...

This is not the intent/expected use. 
   
The intent is to protect the content of the session against being recorded now and decrypted later.

In short, no problem.